[Bug] Web file tree does not refresh after git operations add new directories #18504

Description

When using OpenCode's web interface, the file tree sidebar does not update to show new directories/files that are added via git reset --hard, git pull, or git checkout operations performed by the agent or terminal.

Steps to Reproduce

1. Open OpenCode web UI with a project that has git sub-repositories
2. Have the agent (or manually) run git reset --hard origin/main on a repo where the remote has new directories not present locally
3. Observe the file tree sidebar — new directories do not appear
4. Verify with ls in the terminal that the directories exist on disk

Expected Behavior

The file tree should detect filesystem changes (new directories/files) after git operations and update accordingly.

Actual Behavior

The file tree remains stale and only shows the directory listing from when the session started (or when the tree was last manually expanded). New directories added by git operations are invisible in the UI until the browser page is fully reloaded.

Environment

• OpenCode web interface (Cloud Workstation)
• Linux (Debian-based container)
• Filesystem: persistent home disk + GCS FUSE mount

Suggested Fix

Consider adding a filesystem watcher (e.g., fs.watch or polling) that detects changes in expanded directories, or expose a manual "Refresh" action in the file tree context menu.