feat: add commit panel and file status indicators to repo workspace

- Add CommitPanel component for viewing changed files and committing
- Show file status indicators (M/A/D/?) in file tree
- Integrate git status with workspace for real-time updates
- Add CSS styles for commit panel and status badges

Part of git-control change implementation.

openspec/changes/git-control/proposal.md

@@ -0,0 +1,44 @@
+# Git Control Features
+
+## Problem
+
+The repository workspace currently provides read-only access to git repositories. Users can browse files, view history, and see branches, but cannot perform git operations like creating branches, committing changes, pushing/pulling, or merging.
+
+## Solution
+
+Add git control capabilities to the repository workspace, allowing users to:
+1. Create and delete branches
+2. Switch between branches (checkout)
+3. Commit changes (for quick edits)
+4. Push changes to remote
+5. Pull/fetch updates from remote
+6. Merge branches
+7. View working directory status
+
+## Benefits
+
+- **Complete workflow**: Users can make small changes without leaving the browser
+- **Quick iterations**: Fix typos, update configs, make small adjustments
+- **Branch management**: Create feature branches, merge when done
+- **Remote sync**: Keep repositories up to date
+- **No external tools needed**: Everything in the browser
+
+## Scope
+
+### What stays:
+- Existing file browser and viewer
+- Git history visualization
+- Repository management (create/delete)
+
+### What's new:
+- Branch CRUD operations
+- Working directory status (modified files)
+- Commit operations
+- Push/pull/fetch
+- Merge capabilities
+- Git action toolbar in workspace
+
+### What changes:
+- Workspace toolbar gets git action buttons
+- File viewer gets "modified" indicators
+- Branch selector gets management options