Release v0.19.0: /docs nav + on-site sessions browser

VERSION + CHANGELOG bump for roadmap item #30. The frontend
package.json was bumped alongside the frontend slice; this commit
finalizes the canonical VERSION at 0.19.0 and prepends the v0.19.0
CHANGELOG entry with the operator upgrade-steps block
(OHM_SESSION_HISTORY_RAW_BASE + the two TTL knobs; all MAY) and the
note about graceful degradation when the session-history repo is
still flat at deploy time (subsession 0017.2 ships the restructure
in parallel).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -23,6 +23,18 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## v0.19.0 — 2026-05-28
+
+Roadmap item #30: docs nav with on-site sessions browser. Adds a left-side flyout nav on `/docs/*` and three new public surfaces — `/docs/sessions/about` (renders the session-history README), `/docs/sessions/<NNNN>` (per-session index), `/docs/sessions/<NNNN>/<filename>` (per-transcript view). Backend mediates the fetch from `wiggleverse/ohm-session-history` over gitea raw URLs with a small in-process TTL cache (60 s manifest, 5 min content; both env-tunable). Existing `/docs` content moves to `/docs/user-guide`; bare `/docs` redirects.
+
+Upgrade steps:
+
+MAY: `flotilla overlay set ohm-rfc-app OHM_SESSION_HISTORY_RAW_BASE=<url>` if the deployment points at a non-OHM transcript repo. Default in code matches OHM's `wiggleverse/ohm-session-history`.
+
+MAY: `flotilla overlay set ohm-rfc-app OHM_DOCS_SESSIONS_MANIFEST_TTL_SEC=60` and `OHM_DOCS_SESSIONS_CONTENT_TTL_SEC=300` to tune cache TTLs.
+
+Note: this release depends on the parallel restructure of `wiggleverse/ohm-session-history` into per-session `NNNN/` folders + `README.md` + `sessions.json` (driver session 0017.0, subsession 0017.2). If the repo is still flat at deploy time, `/docs/sessions/about` and the per-session pages return 404 and the route tree degrades to "About not yet published" — no JS crashes; the User Guide remains fully functional.
+
 ## 0.18.0 — 2026-05-28
 
 **Minor — schema migration required; one env var now mandatory; no

VERSION

@@ -1 +1 @@
-0.18.0
+0.19.0