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/wiki/Working-With-Files.md

@@ -175,8 +175,8 @@ Click it for a draggable window, in the style of the File Viewer:
 - **Uncommitted changes**, grouped as staged, not staged, untracked and conflicted, each with a
   status letter (`M` modified, `A` added, `D` deleted, `R` renamed, `?` new, `U` conflict).
 - **Not pushed**: the commits no remote has. A branch with no upstream says so, and so does one whose
-  upstream was deleted on the remote ("Upstream is gone"), which counts every commit on no remote
-  rather than showing a green tick.
+  upstream does not exist on the remote, because it was never pushed or was deleted there ("Upstream
+  not on remote"), which counts every commit on no remote rather than showing a green tick.
 - Files are grouped under their folders, collapsed until you click a folder (a chain of single-child
   folders is one row, and the folders you opened stay open when the list refreshes). Turn off
   **App Settings → Header & Panels → Bottom bar → Git status: group files by folder** for a flat