fix(edit-history): re-read at the end of a turn on session:idle

transcript:complete fires on a `result` line, and claude's interactive transcript has
none (checked against a live session: user/assistant/system turn_duration, no result),
so an open panel never re-read at the end of a turn. A background subagent writes after
the Agent tool end that started it, so its edits stayed missing until the next edit-
capable tool end or a manual refresh.

The panel now re-reads on its session's session:idle, through _onSessionIdle (the SSE
handler map holds one handler per event). Live: a backgrounded subagent's Write shows
up in the open panel at the end of the turn, without a click.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -726,7 +726,7 @@ Matching semantics: a query containing `/` matches the relative path, otherwise
 
 **Edit history panel** (issue #643; `showEditHistory`, per-device, default OFF): which files a local claude session edited (main agent and subagents), each edit's diff, and images a Bash call produced, read from the session's transcripts by byte offset, never from git. Parser `src/edit-history-parse.ts` (pure), store `src/edit-history-store.ts`, reader `src/edit-history-local-source.ts`, sync `src/web/edit-history-sync.ts`, routes `src/web/routes/edit-history-routes.ts` (`GET /api/sessions/:id/edits[?sync=1]`, `GET …/edits/:entryId`, `POST …/edits/older`, all through `findSessionOrFail` WITH `req`), panel `edit-history-ui.js`. User guide: `docs/wiki/Working-With-Files.md` § Edit history.
 
-⚠️ **Reads only on request, opt-in all the way down.** `server.ts` builds the `EditHistorySync` and hands it to the routes; its only own calls are `remove` (through `forgetEditHistory`, when the session's persisted record goes) and `flushAll` (shutdown). No hook, no timer, no second watcher. The panel drives every read: `?sync=1` when it opens, and while it is open on that session a debounced (600 ms) re-read after a `transcript:tool_end` of an edit-capable tool (Edit, Write, MultiEdit, NotebookEdit, Bash, Agent, Task, SendUserFile) or a `transcript:complete`, both events the existing `TranscriptWatcher` already broadcasts. A closed panel reads nothing and keeps no badge. Guarded by the "reads only on request" wiring test in `test/edit-history-sync.test.ts`.
+⚠️ **Reads only on request, opt-in all the way down.** `server.ts` builds the `EditHistorySync` and hands it to the routes; its only own calls are `remove` (through `forgetEditHistory`, when the session's persisted record goes) and `flushAll` (shutdown). No hook, no timer, no second watcher. The panel drives every read: `?sync=1` when it opens, and while it is open on that session a debounced (600 ms) re-read after a `transcript:tool_end` of an edit-capable tool (Edit, Write, MultiEdit, NotebookEdit, Bash, Agent, Task, SendUserFile), which the existing `TranscriptWatcher` already broadcasts, or the session's `session:idle` (the end of a turn, via `_onSessionIdle`; it also catches a background subagent that writes after the tool end that started it). Not `transcript:complete`: it fires on a `result` line, which claude's interactive transcript never has. A closed panel reads nothing and keeps no badge. Guarded by the "reads only on request" wiring test in `test/edit-history-sync.test.ts`.
 
 ⚠️ **Which transcript** (`resolveClaudeTranscript`). The main transcript is the path the session's `TranscriptWatcher` follows (the hook-reported `transcript_path`), so a session is read from where its claude really writes, whatever its `CLAUDE_CONFIG_DIR`. Without a watcher (server restarted, no hook since), `findClaudeTranscript()` looks for `<claudeSessionId|id>.jsonl` under `claudeProjectsDir(session.claudeConfigDir())`: the session's own override (#255, the same dir the relaunch pin checks), else the server's. A config dir set outside Codeman (a shell profile, a wrapper) is never guessed: until the next hook such a session answers `unavailable` / `no-transcript`, and the panel says so. Subagents are `<main path without .jsonl>/subagents/agent-<id>.jsonl`. A different main file (`/clear`, resume) is read from its end with fresh cursors; the stored entries stay.