fix(edit-history): review round 3 — restored sessions read again, /clear reads the old conversation to its end, bounded memory

- remove() drops the session's slot once the file is gone: a session that comes
  back with the same id (reboot restore) starts afresh instead of answering
  `removed` until the next restart. A run in flight stays on its own slot's store,
  and the routes start a sync in the same tick as their session check, so a
  deletion right after it still stops that sync. A store that is not loaded is
  deleted without being parsed (deleteStore).
- A new conversation (/clear, resume) first reads the previous transcript, next
  to the new one, to its end with its subagents, so edits it got after the last
  read are not lost with its cursors. "Load older" reads the stored conversation
  while the switch is pending.
- At most MAX_LOADED_STORES (3) stores stay in memory; the least recently used one
  without a run is written if it changed (settle) and loads again on demand.
- Tmp files are named per process start, so a reused pid (a container's pid 1)
  no longer keeps a stale one through the startup sweep.
- load() keeps only a plain transcript id (the previous transcript's path is built
  from it) and no cursors without one; a pending Bash call with an id, cwd or
  agent id over 4,096 characters is not kept at parse time either.
- nextRange() is gone: production reads forward through the reader. The store
  tests mirror the reader's range choice, and a new end-to-end test runs the
  real reader, sync and store (/clear cases, 40 seeded random transcripts).
- The wiring guard scans all of src for holders of the sync.

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

docs/api-reference.md

@@ -1087,11 +1087,11 @@ Lists are capped (300 files and 50 commits per repository) while the counts stay
 
 What the Edit history panel reads (Settings → Header & Panels → Header, per-device, default off): the edits a **local claude session** made, main agent and subagents, read from its transcripts. Read-only. Every route resolves the session through `findSessionOrFail` (another user's session is `404`). Remote, Docker and non-claude sessions answer `state: 'unsupported'` and are never read.
 
-`GET /api/sessions/:id/edits[?sync=1]` lists the stored edits, newest first, without diffs: `{ state, reason?, backfillTruncated, agents, entries }`. With `sync=1` it first reads what the transcripts gained since the last read; without it the server reads nothing. `state` is `ok`, `unavailable` (stored entries only; `reason` is `no-transcript` before the session has a transcript Codeman can find, `removed` once the session's history was deleted, or the read error; the transcript is the one the session's hooks report, else the newest `<id>.jsonl` under the session's `CLAUDE_CONFIG_DIR` override or the server's config dir) or `unsupported` (`reason`: `remote`, `docker`, `mode`). Each entry is `{ id, ts, path, relPath, kind: 'code'|'image', tool, created, added, removed, truncated, agentId? }`, where `tool` is the edit tool, `bash` for an image a Bash call produced or `sent` for one the agent sent; `relPath` is relative to the workspace (a subagent's worktree for its edits). `agents` maps a subagent id to `{ description, agentType, worktreeBranch? }`. `backfillTruncated: true` means older edits can still be loaded.
+`GET /api/sessions/:id/edits[?sync=1]` lists the stored edits, newest first, without diffs: `{ state, reason?, backfillTruncated, agents, entries }`. With `sync=1` it first reads what the transcripts gained since the last read (after `/clear` or a resume, the previous conversation's transcripts to their end first); without it the server reads nothing. `state` is `ok`, `unavailable` (stored entries only; `reason` is `no-transcript` before the session has a transcript Codeman can find, `removed` while the session's history is being deleted, or the read error; the transcript is the one the session's hooks report, else the newest `<id>.jsonl` under the session's `CLAUDE_CONFIG_DIR` override or the server's config dir) or `unsupported` (`reason`: `remote`, `docker`, `mode`). Each entry is `{ id, ts, path, relPath, kind: 'code'|'image', tool, created, added, removed, truncated, agentId? }`, where `tool` is the edit tool, `bash` for an image a Bash call produced or `sent` for one the agent sent; `relPath` is relative to the workspace (a subagent's worktree for its edits). `agents` maps a subagent id to `{ description, agentType, worktreeBranch? }`. `backfillTruncated: true` means older edits can still be loaded.
 
 `GET /api/sessions/:id/edits/:entryId` returns one edit's diff as unified text: `{ diff, truncated }` (each edit's diff is capped at 64 KiB). `404` for an edit the session does not have.
 
-`POST /api/sessions/:id/edits/older` reads the next older block of up to three transcripts, a full read budget each (with more transcripts, main and subagents take turns), and answers like the list.
+`POST /api/sessions/:id/edits/older` reads the next older block, within the current conversation, of up to three transcripts, a full read budget each (with more transcripts, main and subagents take turns), and answers like the list.
 
 The edits are stored per session in `~/.codeman/edit-history/<id>.json` (mode 0600, at most 500 edits and 4 MiB of diff text, the oldest dropped), deleted when the session's record is removed (a killed pinned session keeps it; at startup, a file whose session no longer exists is deleted too) and never fed into `/api/v1/search`. No route here serves a file: the panel shows thumbnails through `file-raw` inside the workspace only; an image outside it opens in the file preview, which registers it through the attachment route.