fix(git-status): landing fixes (#537)

- A cached list of repositories below a folder is re-checked against the
  Docker case workspaces as they are now, so a repository linked as a Docker
  workspace within the 30 s list cache is no longer inspected.
- A diff past runGit's 8 MB output bound is cut short from git's partial
  output instead of failing with a 500.
- The browser test waits for its slow route handler on unroute
  (unrouteAll behavior 'wait'), so a late route.continue() cannot fail the run.
- "Upstream is gone" now reads "Upstream not on remote", true for a branch
  that was never pushed as well as one deleted on the remote; docs mirrored.
- The diff route checks the repository against the workspace's own cached
  repository list (findWorkspaceRepo) and refreshes only that repository,
  instead of a fresh status of every repository in the folder.
- CLAUDE.md: a Key Patterns entry for the git read surface and its rules.
- The enclosing repository is identified with one cached rev-parse before
  any full status, so an unrelated repository above the workspace costs one
  process and its failure no longer hides the repositories below.
- Wiki: the bottom-bar indicator moves out of the header-controls table.

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

docs/api-reference.md

@@ -717,7 +717,7 @@ Admin only in multi-user mode (`403`), like `POST /api/cases/link`: it writes ou
 
 ## Git status
 
-`GET /api/sessions/:id/git-status` is what the bottom-bar Git indicator and its panel read (Settings → Header & Panels → Bottom bar, per-device, default off). It reports what the session's workspace has not committed or pushed. **Read-only and offline:** it never fetches, pulls, commits or writes (it runs `git status` with `--no-optional-locks`, so it does not even refresh the index), which is why `behind` is as of the last `git fetch`. The session is resolved like every session route (ownership via `findSessionOrFail`; another user's session is `404`). A repository whose root is, or is inside, a Docker case workspace is dropped (from the walk-up, the scan below a folder, and the diff route): a container can write there, and a repository's own clean filter or signature program would run on the host. When a branch's upstream was deleted and pruned on the remote, `upstreamGone` is `true` and the unpushed list falls back to commits on no remote-tracking ref at all.
+`GET /api/sessions/:id/git-status` is what the bottom-bar Git indicator and its panel read (Settings → Header & Panels → Bottom bar, per-device, default off). It reports what the session's workspace has not committed or pushed. **Read-only and offline:** it never fetches, pulls, commits or writes (it runs `git status` with `--no-optional-locks`, so it does not even refresh the index), which is why `behind` is as of the last `git fetch`. The session is resolved like every session route (ownership via `findSessionOrFail`; another user's session is `404`). A repository whose root is, or is inside, a Docker case workspace is dropped (from the walk-up, the scan below a folder, and the diff route): a container can write there, and a repository's own clean filter or signature program would run on the host. When a branch's upstream does not exist on the remote (deleted and pruned, or never pushed, as after cloning an empty repository and committing), `upstreamGone` is `true` and the unpushed list falls back to commits on no remote-tracking ref at all.
 
 `GET /api/sessions/:id/git-diff?repo=<repoRoot>&path=<path>&kind=staged|unstaged|untracked|conflicted` returns the unified diff of one file the panel lists (`{ diff, truncated, binary }`; staged is index vs HEAD, unstaged is working tree vs index, untracked is the whole file as additions). It is what opens when you click a file in the Git panel. `repo` and `path` are matched against the current status rather than trusted, so anything the status does not list is `404`. Read-only: it passes `--no-ext-diff --no-textconv` (no external diff or textconv driver runs), but a repository's clean filters still run, as they do for any `git diff`, which is why a repository a container can write to is never inspected (below). Capped at 400 KB, and refused (`400`) for remote and Docker sessions; a repository at or inside a Docker case workspace is not in the status, so it is `404` here.