feat: workspace-first UI refresh - PR-2 workspace detail page

- Add workspace detail page (/workspaces/:id) with 4 tabs:
  - Files: file tree, viewer, editor, git toolbar (commit/push/pull/fetch)
  - Git: branch selector, commit history
  - Tools: instance grid, start tool modal
  - Settings: workspace info read-only
- Add workspace API clients: workspace-files, workspace-git, workspace-instances
- Add hooks: useWorkspaceFiles, useWorkspaceGit, useWorkspaceInstances
- WorkspaceCard links to detail page via router Link
- Add comprehensive CSS for workspace detail layout
- Mobile: bottom tab bar, responsive file tree/split
- TypeScript + eslint clean

Quality gates: tsc --noEmit clean, eslint clean

apps/api/src/services/git_operations.py

@@ -111,9 +111,7 @@ class GitOperations:
         if rc != 0:
             raise RuntimeError(f"Git add failed: {err}")
 
-        rc, _, err = await self._run(
-            "git", "-C", self.cwd, "commit", "-m", message
-        )
+        rc, _, err = await self._run("git", "-C", self.cwd, "commit", "-m", message)
         if rc != 0:
             raise RuntimeError(f"Git commit failed: {err}")