F4: document propose/accept — manual smoke, README, playground loop (#12)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

docs/MANUAL-SMOKE-F3.md

@@ -1,5 +1,10 @@
 # F3 manual smoke — live `claude-code` turn (spec §6.8)
 
+> **As of F4 (#12)** the edit-selection turn ends in a **proposal** — the
+> direct-apply behavior in §2 step 4 now happens on **✓ Accept Proposal**. The
+> full propose→accept smoke is [`MANUAL-SMOKE-F4.md`](./MANUAL-SMOKE-F4.md);
+> §1's scripted smoke is unchanged (it drives the SDK turn only, no editor).
+
 The live turn is deliberately NOT in CI (unit + host E2E drive the seam). It
 gets this documented smoke, run once per machine that has Claude Code
 installed and signed in (Pro/Max). The extension itself holds no credentials
@@ -37,9 +42,9 @@ the model id, a non-empty `sessionId`, and exits 0.
   with a clear error (`runEditTurn` throws on any non-`completed` run
   status); in-editor, the command shows an error notification and NO edit is
   applied.
-- Buffer edited mid-turn: start an edit-selection turn, type elsewhere in the
-  document before it completes → warning notification "document changed", no
-  partial application (stale `expectedVersion`, spec §6.9).
+- Buffer edited mid-turn: superseded by F4 — the turn ends in a proposal, so a
+  mid-turn edit can't race an application; the proposal simply renders where
+  its target re-resolves (or stale if the target itself changed — F4 INV-11).
 
 ## Smoke log