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>

src/web/public/git-status-ui.js

@@ -399,8 +399,9 @@ Object.assign(CodemanApp.prototype, {
     const line = el('div', 'git-status-branchline');
     if (data.upstream && data.upstreamGone) {
       line.append(el('span', 'git-status-chip', `${data.branch || 'HEAD'} → ${data.upstream}`));
-      const gone = el('span', 'git-status-chip git-status-chip--warn', 'Upstream is gone');
-      gone.title = 'The remote branch was deleted (and pruned), so the commits below are on no remote.';
+      const gone = el('span', 'git-status-chip git-status-chip--warn', 'Upstream not on remote');
+      gone.title =
+        'The upstream branch does not exist on the remote (never pushed, or deleted and pruned), so the commits below are on no remote.';
       line.append(gone);
     } else if (data.upstream) {
       line.append(el('span', 'git-status-chip', `${data.branch || 'HEAD'} → ${data.upstream}`));
@@ -473,7 +474,7 @@ Object.assign(CodemanApp.prototype, {
             'div',
             'git-status-note',
             data.upstreamGone
-              ? 'The upstream branch is gone from the remote, so these commits are on no remote.'
+              ? 'The upstream branch does not exist on the remote (never pushed, or deleted), so these commits are on no remote.'
               : 'This branch has no upstream, so these commits are on no remote yet.'
           )
         );