feat(dial): snap to the closest altitude on drag release

A drag is a way of grabbing the altitude dial, not a free-standing encoder
detent. Until now onDialUp held the live blend wherever the knob stopped (the
"no auto-complete" model), so a grab-and-release could leave the experience
parked mid-morph between two altitudes.

Now a real turn (moved >= 6) auto-scrubs the short way to Math.round(pos) and
settles there (frac 0 locks) — a grab-and-release always lands on a discrete
altitude, exactly like a tap or label click. The tap path (moved < 6 ->
jumpToScale) is unchanged, and reduced motion is handled by autoScrub (jump to
target, no tween).

Adds an altitude-lock e2e asserting a partial drag settles on an integer
altitude after release. Full altitude-lock (14) + a11y + i18n suites green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/hooks/worktree-guard.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# Worktree isolation guard. This repo is worked by MULTIPLE concurrent sessions; if
+# they share the main checkout they clobber each other (branch switches, lost edits,
+# commits on the wrong branch). Every session must work in its OWN git worktree
+# OUTSIDE the main directory.
+#
+#   worktree-guard.sh block    PreToolUse(Edit|Write|NotebookEdit) — DENY edits to
+#                              files INSIDE the main checkout while in it. Files
+#                              outside the repo (memory, /tmp, scratchpad) are allowed.
+#   worktree-guard.sh notice   SessionStart — tell the agent to enter a worktree.
+#
+# Isolated = the session sits in a git worktree, where `--git-dir` (…/.git/worktrees/
+# <name>) differs from `--git-common-dir` (…/.git). Equal = the shared main checkout.
+set -u
+mode="${1:-notice}"
+
+gd=$(git rev-parse --absolute-git-dir 2>/dev/null) || exit 0      # not a repo → nothing to guard
+gc=$(cd "$(git rev-parse --git-common-dir 2>/dev/null)" 2>/dev/null && pwd -P) || exit 0
+[ "$gd" = "$gc" ] || exit 0                                       # already in a worktree → allow
+
+root=$(git rev-parse --show-toplevel 2>/dev/null)
+repo=$(basename "${root:-repo}")
+guidance="You are in the SHARED main checkout ($root). Multiple sessions use it \
+concurrently and WILL clobber each other. Work in an isolated worktree OUTSIDE the \
+main directory: use the EnterWorktree tool (preferred — it relocates this session to \
+a fresh worktree branched from origin/main), or run \
+\`git worktree add -b <branch> ../${repo}-worktrees/<name> origin/main\` and cd there. \
+Do NOT edit files in the main checkout."
+
+esc() { printf '%s' "$1" | python3 -c 'import json,sys; print(json.dumps(sys.stdin.read()))'; }
+
+if [ "$mode" = "block" ]; then
+  # Only guard files INSIDE the main checkout's working tree; allow edits to files
+  # outside the repo (auto-memory, /tmp, scratchpad, other repos).
+  fp=$(python3 -c 'import json,sys
+try:
+    d=json.load(sys.stdin); print(d.get("tool_input",{}).get("file_path","") or "")
+except Exception: print("")' 2>/dev/null)
+  case "$fp" in
+    /*) abs="$fp" ;;
+    "") abs="$root" ;;
+    *)  abs="$root/$fp" ;;
+  esac
+  case "$abs" in
+    "$root"/*|"$root") : ;;   # inside the repo → fall through to deny
+    *) exit 0 ;;              # outside the repo → allow
+  esac
+  printf '{"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecision":"deny","permissionDecisionReason":%s}}\n' "$(esc "$guidance")"
+else
+  printf '{"hookSpecificOutput":{"hookEventName":"SessionStart","additionalContext":%s}}\n' "$(esc "⚠ WORKTREE ISOLATION REQUIRED. $guidance")"
+fi

.claude/settings.json

@@ -0,0 +1,30 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "worktree": {
+    "bgIsolation": "worktree",
+    "baseRef": "fresh"
+  },
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "bash \"$CLAUDE_PROJECT_DIR/.claude/hooks/worktree-guard.sh\" notice"
+          }
+        ]
+      }
+    ],
+    "PreToolUse": [
+      {
+        "matcher": "Edit|Write|NotebookEdit",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "bash \"$CLAUDE_PROJECT_DIR/.claude/hooks/worktree-guard.sh\" block"
+          }
+        ]
+      }
+    ]
+  }
+}

sessions/0034/SESSION-0034.0-TRANSCRIPT-2026-06-30T07-24--2026-06-30T10-01.md

@@ -0,0 +1,107 @@
+# Session 0034.0 — Transcript
+
+> App: human-experience-filter-art
+> Start: 2026-06-30T07-24 (PST)
+> End: 2026-06-30T10-01 (PST)
+> Type: planning-and-executing
+> Posture: yolo
+> Claude-Session: 08b95eb0-3ec5-400a-9236-da78f01139a0
+> Checkout: /Users/benstull/git/benstull.org/benstull/human-experience-filter-art/.claude/worktrees/fix+audio-and-tracking-labels
+> Status: FINALIZED
+
+## Launch prompt
+
+> The audio isn't playing at all. Let's fix that and then let's make sure there are
+> left and right brain tracking labels for everything. Make sure you're working on a
+> worktree. There are other concurrent sessions that may have real merge conflicts to
+> handle.
+
+## Pre-state
+
+- The simulator (`simulator/`) is a FastAPI + static-JS experience: an altitude dial
+  over 6 scales (cosmos/orbit/sky/coast/reef/abyss), 41 rotating-pool clips, a
+  real-time Kuwahara "dream" shader, two HUD label layers — **Think** (left-brain
+  factual chips, `#overlay`) and **Feel** (right-brain affect words, `#affect`) —
+  plus a per-altitude soundtrack with a 0–10 audio dial and a built-in
+  `#audio-status` diagnostic.
+- s0027 had brought all 41 clips to left+right annotation with 4-lang parity, but the
+  left labels were thin (many clips 1–2) and STATIC; affect was authored PER-SCALE
+  (every clip in an altitude shared 4 feelings).
+- Operator was running a stale `:8000` server on the `design/cloudflare-static-publish`
+  branch (a concurrent session's WIP — "Run simulation" begin-experience flow, +
+  later a credits page). Project is EXEMPT from the Wiggleverse deploy pipeline
+  (flotilla/PPE/§9); public target is static Cloudflare. cv2/imageio NOT installed in
+  this env.
+
+## Session arc
+
+1. **Worktree.** Created native worktree `fix+audio-and-tracking-labels` off
+   `origin/main` (582183d). All work done here.
+2. **Audio (systematic-debugging) — FALSE ALARM.** Could not reproduce "no audio" in
+   ANY automated condition: Chromium + WebKit, strict autoplay
+   (`--autoplay-policy=user-gesture-required`), clean-main server AND the operator's
+   `:8000` WIP server, via Video-toggle / Audio-dial / "Run simulation" button; all 5
+   soundtracks decode to real non-silent audio (RMS 0.08–0.24). The raw
+   native-controls `#aud-test` player was ALSO silent on the operator's Safari while
+   the element reported playing → isolated it BELOW the app. Operator confirmed:
+   **their Safari sound was muted.** No code change.
+3. **"Labels not showing" on cosmos_tarantula.** Root cause: operator was on `:8000`
+   (design branch), whose manifest had that clip's `annotations: []`. My branch
+   renders all labels correctly; labels are knob-gated (none at Think/Feel 0).
+4. **Left (Think) enrichment.** Every clip → ≥3 factual labels (added one to each of
+   23 thin clips; orbit_bluemarble 1→3), full es/fr/ja parity. Pipeline:
+   `LABELS` in `build_pool_manifest.py` → build → catalogs → `translate_manifest.py
+   merge`. (commit `8cfceff`)
+5. **Motion-tracking.** Converted the 4 still-static abyss creatures (octopus, bigfin
+   squid, dandelion siphonophore, sea pig) static→tracked, 3-keyframe paths sampled
+   by eye from frames (cv2 unavailable). Tracked clips 7→11. (`8cfceff`)
+6. **Think/Feel overlap avoidance.** `renderAffect` now nudges Feel words off Think
+   chip plates (obstacles computed from manifest, tracked paths sampled → holds whole
+   loop, no per-frame jitter; new `window.__hefNoDeconflict` seam). Verified 0
+   overlaps across all 6 scales incl. a tracked clip over time. (commit `041fcde`)
+7. **Per-clip right-brain feelings.** Operator: feelings should match each ACTUAL
+   video. Added `AFFECT_CLIP` (per-clip override, scale fallback) for all 41 clips →
+   41 distinct feeling-sets. cosmos done by me as a reviewed sample; the other 5
+   scales drafted by **5 parallel subagents** (one per scale) that each VIEWED footage
+   frames and followed the cosmos recipe; I normalized + authored all es/fr/ja for the
+   19 new nuance keys. 42 distinct feeling keys now. (commits `bf1013b` + `2d54023`)
+8. **Merge.** Merged branch → `origin/main` (clean; main had only advanced by
+   `sessions/` transcript commits). Confirmed all 4 work commits are ancestors of
+   `origin/main`; another session (`feat/accessibility-pass`) has since merged main +
+   a11y on top (`380c2d1`).
+
+## Cut state (final)
+
+- All work committed, merged to `origin/main`, pushed. Working tree clean.
+- Verification: 34/34 catalog+i18n+build pytest, 16/16 node unit, live render shows
+  ≥3 Think chips + distinct Feel words per clip (incl. new keys) with overlap 0 and no
+  JS errors. (3 unrelated pytest failures = cv2/ffmpeg absent in this env.)
+- Worktree RETAINED (not torn down) because it is serving the operator's by-eye review
+  at `http://127.0.0.1:8011/author.html`; tear down + stop `:8011` when review done.
+- §9 deploy pipeline: N/A — project is exempt (static Cloudflare target).
+
+## Deferred decisions (low-confidence calls)
+
+- **Audio = no code change.** Chose to treat it as environmental after exhaustive
+  repro rather than guess-patch a working engine; operator confirmed muted Safari.
+- **Left-label box positions authored WITHOUT viewing each frame** (23 enriched
+  clips, except bluemarble) — factual text is grounded, positions are estimates that
+  want by-eye review.
+- **Per-clip feelings drafted from a single MID-FRAME** (motion not seen) via parallel
+  subagents — first-pass reads; emotions may want tuning once a clip is in motion.
+- **Left reef/coast moving-subject clips left STATIC** (reef_redsea/flowergarden
+  schools, coast_otters/seals) — tracking deferred (diffuse subjects + cv2 absent).
+- **Merged directly to `main` via `git push HEAD:main`** (no Gitea PR) at operator's
+  explicit request; gh is GitHub-only here and no `tea` CLI.
+
+## Operator plate
+
+- Review the first-pass label/track/feeling positions in `/author.html` on `:8011`.
+- For Think: check each chip sits on its subject + the 4 abyss tracks follow the
+  creature. For Feel: check emotions ring true once clips are in motion.
+
+## Next /goal
+
+```
+/goal refine the first-pass left-label box positions and the 4 abyss creature tracks per operator by-eye review (grab a frame per clip, nudge each chip onto its subject), and motion-track the remaining moving-subject clips (reef schools, coast animals) — data-only via build_pool_manifest + i18n pipeline
+```

sessions/0035/SESSION-0035.0-TRANSCRIPT-2026-06-30T08-45--2026-06-30T10-08.md

@@ -0,0 +1,102 @@
+# Session 0035.0 — Transcript
+
+> App: human-experience-filter-art
+> Start: 2026-06-30T08-45 (PST)
+> End: 2026-06-30T10-08 (PST)
+> Type: planning-and-executing
+> Posture: yolo
+> Claude-Session: ee3eaaac-d0a4-41a9-aa53-1919052fd8d3
+> Checkout: /Users/benstull/git/benstull.org/benstull/human-experience-filter-art
+> Status: **FINALIZED**
+
+## Launch prompt
+
+Not a `/goal` launch. Opened conversationally: "We need to make the entire
+simulator accessible, assuming it's not being used at a kiosk. What are the
+different types of accessibility and your suggestions (and difficulty)?" Then:
+build the first pass on a worktree, and add an `about.html` about the project's
+intent (accessible to all humans; vantage points from underwater→drones→space
+exploration; built with LLMs; honest that it's imperfect but more than the author
+alone could make).
+
+Drove through the **superpowers** pipeline (brainstorming → writing-plans →
+executing-plans → finishing-a-development-branch), not a wgl init — so the wgl
+transcript ID was claimed at finalize (this file).
+
+## Pre-state
+
+- Simulator built for an attended **kiosk**; the Cloudflare static publish
+  (`design/cloudflare-static-publish`, already merged to `main` mid-session as
+  `87d605d`) puts it on a public URL where no AT/attendant assumptions hold.
+- No `prefers-reduced-motion`, no keyboard on the SVG Altitude dial, several
+  failing-contrast colors, no screen-reader path, no seizure safeguard — on a
+  piece that is continuous motion + a "trippy at max" WebGL shader.
+
+## Arc (turn-by-turn)
+
+1. **Analysis** — read `index.html` / `style.css`, grepped `app.js` (zero aria /
+   keyboard / reduced-motion). Enumerated 7 accessibility types grounded in the
+   actual UI, with difficulty + a priority table. Recommended WCAG 2.1 AA + a
+   motion/seizure layer.
+2. **Brainstorming** — operator chose: reduced-motion = **freeze-to-stills**;
+   photosensitivity = **warning gate + flash audit**; about page = **English-first**.
+   Added the about-page "imperfect but more than alone" beat. Wrote + committed the
+   design spec.
+3. **Worktree** — first tried `EnterWorktree` (branches off `origin/main`); on
+   inspecting the diff, the work belonged on `design/cloudflare-static-publish`
+   (correct `app.js`, existing `credits.html` pattern). Operator: "new worktree off
+   that, keep separate until ready for main." Created
+   `feat/accessibility-pass` off the design branch under `.claude/worktrees/`.
+4. **Plan** — 10 bite-sized TDD tasks, committed.
+5. **Execution (TDD, test-first each)** — (1) layout: lang picker below Audio,
+   globe inline-left; (2) AA contrast + focus-visible + visually-hidden; (3)
+   `flash.js` pure WCAG-2.3.1 helper + node tests; (4) one-time photosensitivity
+   gate; (5) reduced-motion freeze (single `playLoop()` guard + instant `autoScrub`);
+   (6) keyboard/ARIA dial (`role=slider`, Arrow/Home/End, label buttons); (7)
+   aria-live narration + `aria-hidden` decoratives; (8) wire flash-clamp + document
+   audit (no breach found); (9) `about.html` + header link + `PUBLIC_ASSETS`.
+   9 a11y e2e + 2 node tests, all green; fixed a gate-vs-run-sim regression in the
+   shared `boot()` helper.
+6. **Finish** — operator: merge everything to main + push origin. `origin/main`
+   had advanced 29 commits (static-publish already landed there) → divergent merge;
+   one `app.js` conflict (main's D3 reverse-landing fix vs my reduced-motion guard)
+   resolved keeping **both**. Re-verified on merged code (a11y 9/9, altitude-lock
+   13/13, i18n 1/1, static-build 2/2, flash 2/2). Pushed `ff06783..380c2d1 main`.
+   Removed the worktree; stopped bg servers.
+
+## Cut state
+
+- **a11y pass + About page MERGED + PUSHED to `origin/main` (`380c2d1`).**
+- On `main` but **NOT deployed** — live benstull.art needs a Cloudflare redeploy.
+- App has **no content repo** → plan stays in-repo at
+  `docs/superpowers/plans/2026-06-30-accessibility-and-about-page.md`. No
+  `submit-plan.sh`. Project is **exempt** from §9/flotilla/PPE (Cloudflare static).
+- A **concurrent** commit `1a6ffc7` ("phase-1 preload gate") sits on local `main`
+  ahead of origin by 1 — **not this session's; left untouched/unpushed** per
+  operator ("leave anything that isn't yours alone"). Other worktree
+  `fix+audio-and-tracking-labels` also left alone.
+- Checkout now on `main` (was `design/cloudflare-static-publish` at start).
+
+## Deferred decisions
+
+_Autonomous low-confidence calls (no live placeholder existed, so logged here):_
+
+- **SR narration = scale + clip title**, not the tiered factual (Think) HUD label —
+  simpler/robust; the plan explicitly permitted the degrade. Could enrich later.
+- **Flash audit concluded no >3/sec breach** (1200ms per-altitude floor; fades are
+  single, ≥1.2s apart); `flash.js` wired only as a guard floor (no-op today).
+- **Branched off the design branch, not main** — corrected after operator input.
+- **Merged the full divergent history to main** (static-publish was already on
+  origin/main, so net-new was just the a11y work) — on explicit operator instruction.
+
+## Next /goal
+
+```
+/goal redeploy benstull.art/human-experience-simulator to Cloudflare so the accessibility pass + About page go live, per cloudflare-deploy-live (build with `python3 -m tools.build_static`, then the R2/Pages deploy gestures)
+```
+
+Operator by-eye review of the a11y changes precedes the redeploy. Env gotchas for
+the next session: run `build_static` as a **module** (`python3 -m tools.build_static`)
+or `tools/http.py` shadows stdlib `http`; uvicorn dies mid-session and the e2e
+`webServer` fallback calls `python` (only `python3` here) → start it by hand on :8099;
+Playwright `test.use()` inside `test.describe()` breaks collection in PW 1.45.

sessions/0036/SESSION-0036.0-TRANSCRIPT-2026-06-30T06-30--2026-06-30T12-00.md

@@ -0,0 +1,108 @@
+# Session 0036.0 — Transcript
+
+> App: human-experience-filter-art
+> Start: 2026-06-30T06-30 (PST)
+> Type: planning-and-executing
+> Posture: yolo
+> Claude-Session: a7814ad4-473f-4946-b158-a5fad35b4bf1
+> Checkout: /Users/benstull/git/benstull.org/benstull/human-experience-filter-art
+> Status: finalized
+
+## Launch prompt
+
+"Let's publish this to benstull.art. Ideally this would be hosted on Cloudflare
+Pages. Cloudflare Pages does have limits though, so we should check that against
+this project." (Started conversationally — no tracked init; finalized as
+planning-and-executing/yolo.)
+
+## Pre-state
+
+The simulator was a FastAPI server (`simulator/app.py`) serving a ~92 KB static
+frontend + 3.9 GB of media (1080p clip bases + 558 already-720p transition morphs +
+audio) via dynamic endpoints. Not yet public anywhere. Operator wanted it live at
+benstull.art on Cloudflare Pages. Concurrent sessions (0029/0031/0033/0034/0035)
+were active on the SAME checkout.
+
+## Arc
+
+**1. Brainstorm → design → plan (Cloudflare publish).** Established the blocker:
+Pages has a 25 MiB/file hard limit; the project has 26 files >25 MiB. Designed a
+fully-static target: Pages frontend + R2 media (no per-file limit, free egress) +
+read-APIs baked to JSON + client-side pick + `/api/alteration` ported to JS.
+Operator chose: both tiers irrelevant→dropped; path `/human-experience-simulator`
+with apex redirect; no cross-session cache (initially). Spec + plan written under
+`docs/superpowers/`. Operator declared the WHOLE project exempt from flotilla/PPE/§9.
+
+**2. Executed the plan (5 tasks).** Client-side alteration engine (`alteration.js`
++ node/py parity tests); config-driven `mediaBase` + baked-JSON boot + client pick +
+`crossOrigin` for the WebGL dream shader; `tools/build_static.py` (dist/ + manifest-
+only ~2.3 GB media tree + `_redirects`); Cloudflare deploy artifacts; static-build
+E2E. Hit + cleanly extracted a parallel session's in-flight "Run simulation" work
+that got swept into a commit (operator chose extraction).
+
+**3. Live deploy.** Installed wrangler; operator did `wrangler login`. Created R2
+bucket `human-experience-simulator-media`, CORS (wrangler's `{rules:[...]}` schema,
+not S3-style), bound `static.benstull.art` via CLI (zone-id from API), parallel
+604-file upload (no `wrangler r2 sync` exists). Created + deployed Pages project;
+operator bound `benstull.art`. **Live.**
+
+**4. Debugging (systematic).** "Morphs not showing" = upload still in progress
+(transitions sort last) → fixed by parallel upload. "Video + audio not playing" →
+drove the LIVE site with Playwright: video fine, **audio 404'd** because
+`scaleAudioUrl` hardcoded `/media/audio/` instead of `mediaBase()` — fixed.
+"Still no video after hard refresh" → **stale cached JS** (Pages caches .js
+max-age=14400, ignores `_headers`) → fixed with content-versioned asset URLs
+(`app.js?v=<hash>`) + no-cache `_headers`. Private-window confirmed fresh code worked.
+
+**5. Preload algorithm.** "Next altitude's video doesn't start" = a buggy
+hold-last-frame settle gate I'd added (gated playLoop behind a canplay that doesn't
+re-fire) → reverted. Operator specified the algorithm: gate on 1 clip/altitude +
+connecting morphs (~126 MB, ~10-20s — measured), then grow the pool in the
+background; the random pick is restricted to fully-loaded (eligible) clips so
+navigation never stalls and new clips are reachable only once fully downloaded.
+Built `preload.js` (pure planner + node tests), wired phase-1 gate + eligible picks.
+
+**6. Worktree isolation enforcement.** The shared checkout caused branch-switch
+chaos (my commits landed on a switched-to `main`). Operator: "make sure every
+session works off a fresh worktree not in the main directory." Built
+`.claude/settings.json` (worktree.bgIsolation + baseRef:fresh) + a PreToolUse hook
+(`worktree-guard.sh`) that DENIES edits to repo files while in the main checkout +
+SessionStart notice → EnterWorktree. Proven live (blocked my own edit); fixed an
+over-broad version that blocked external files too. Dogfooded the merge of guard +
+preload onto origin/main IN an isolated worktree.
+
+## Cut state
+
+- **Live:** https://benstull.art/human-experience-simulator/ — Pages + R2, preload
+  algorithm, audio fixed, cache-versioned. Operator confirmed video+audio work.
+- **origin/main (`a4d3d83`+):** has the Cloudflare publish, preload algorithm, and
+  worktree-isolation guard, merged cleanly with parallel a11y work.
+- Plan archived in-repo (`docs/superpowers/plans/2026-06-30-cloudflare-static-publish.md`),
+  on origin/main. **No `content` repo** → plan stays in-repo (app.json gap).
+- Local `main` checkout is behind origin/main (parallel session actively deploying).
+- Backup branches on origin: `chore/worktree-isolation`, `fix/preload-gate`,
+  `design/cloudflare-static-publish` (content all merged to main; safe to delete).
+
+## Pipeline (§9) status
+
+Operator-set Cloudflare exception (no flotilla/PPE). localhost + **E2E green** (33
+node tests; 13 altitude-lock + 2 static-build Playwright); no PPE (exempt); **prod =
+live** via `make deploy`. Repeatable deploy: `make deploy` / `make deploy-media`
+(`deploy/cloudflare/`).
+
+## Operator plate (next session)
+
+- By-eye/ear review of the live site: load time, video, audio, rapid-altitude
+  navigation smoothness (eligible-pick growth), the preload behavior under real
+  network. The hold/grow path only triggers when media isn't cached — needs eyes.
+- Restart any still-running sessions so they pick up the worktree guard + move to
+  worktrees. Clean up backup branches if desired.
+
+## Deferred decisions
+
+- Estimated session start time (no tracked init) — used 2026-06-30T06-30.
+- Did NOT reconcile local `main` (behind origin/main) — a parallel session is
+  actively deploying origin/main; left the shared checkout untouched to avoid
+  disrupting it.
+- Cross-session Service-Worker disk cache and a 720p base tier were proposed and
+  DEFERRED (morphs already 720p; bases dominate load but per-altitude growth covers it).

sessions/sessions.json

@@ -97,5 +97,14 @@
   },
   "0033": {
     "title": ""
+  },
+  "0034": {
+    "title": ""
+  },
+  "0035": {
+    "title": ""
+  },
+  "0036": {
+    "title": ""
   }
 }

simulator/e2e/tests/altitude-lock.spec.ts

@@ -276,7 +276,8 @@ test("crossing a detent commits and locks the destination clip", async ({ page }
   const box = (await page.locator("#dial").boundingBox())!;
   const cx = box.x + box.width / 2, cy = box.y + box.height / 2;
   // Drag clockwise across one full detent (top -> right ~= 90deg = 1.25 detents),
-  // crossing integer 1 (orbit) so it commits, then hold past it (no auto-complete).
+  // crossing integer 1 (orbit) so it commits, then hold past it WHILE STILL DRAGGING
+  // (the live blend holds wherever the knob is held; the snap happens only on release).
   await page.mouse.move(cx, cy - 30);
   await page.mouse.down();
   await page.mouse.move(cx + 30, cy + 6, { steps: 14 });
@@ -293,3 +294,30 @@ test("crossing a detent commits and locks the destination clip", async ({ page }
   expect(st2.activeClipId).toBe(st.activeClipId);
   await page.mouse.up();
 });
+
+test("releasing a partial drag snaps to the closest altitude (no held mid-blend)", async ({ page }) => {
+  // The operator can grab the dial, turn it PART of a detent, and let go between two
+  // altitudes. On release the knob must auto-scrub to the CLOSEST altitude and settle
+  // there (integer position, frac 0) — landing on a discrete altitude exactly as if
+  // they had clicked it, rather than holding the half-finished blend.
+  await boot(page);
+  const box = (await page.locator("#dial").boundingBox())!;
+  const cx = box.x + box.width / 2, cy = box.y + box.height / 2;
+  await page.mouse.move(cx, cy - 30);
+  await page.mouse.down();
+  await page.mouse.move(cx + 18, cy - 24, { steps: 8 });   // ~0.5 detent — parks BETWEEN altitudes
+  // While held we are mid-blend: a fractional knob position.
+  await page.waitForFunction(
+    () => { const p = (window as any).__hefState().pos; return Math.abs(p - Math.round(p)) > 0.05; },
+    null, { timeout: 5000 },
+  );
+  await page.mouse.up();
+  // After release the position settles on an integer altitude (the snap).
+  await page.waitForFunction(
+    () => Number.isInteger((window as any).__hefState().pos),
+    null, { timeout: 10000 },
+  );
+  const st = await page.evaluate(() => (window as any).__hefState());
+  expect(Number.isInteger(st.pos)).toBe(true);   // landed on an altitude, not held mid-blend
+  expect(st.ringIndex).toBe(st.pos);             // committed altitude == the position it landed on
+});

simulator/static/app.js

@@ -1076,7 +1076,11 @@ function onDialUp(e) {
     }
     return;
   }
-  // No auto-complete: hold the blend wherever the knob stopped (continuous-encoder model).
+  // Snap on release: a drag is a way of GRABBING the dial, not a free-standing
+  // encoder detent — so when the operator lets go between altitudes, auto-scrub the
+  // short way to the CLOSEST one and settle there (frac 0 locks). The result is the
+  // same as a tap/label-click: a grab-and-release always lands on a discrete altitude.
+  autoScrub(Math.round(pos));
 }
 
 // Click a label → auto-scrub the SHORTEST signed way around the ring to that scale.