run an agent from the file browser

Right-click an entry and agents whose triggers match appear under their own Run Agent
submenu — deliberately not folded in with tasks, because an agent run is a chat session and
not a job, and one menu promising both would lie about what a click does. The modal shows the
absolute target path, autofills entry_path with it (tilde expansion stays the server's job),
and on Run links to /chat?cwd=<runs dir> instead of a queue entry: there is no job row to view.

Trigger matching and category grouping are now shared with tasks rather than duplicated, and
the task input form is reused as-is.

Rescan counts agents and invalidates their caches, so a new AGENT.md shows up on the button
rather than after the 60s staleTime.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/servers/api/items/rescan.ts

@@ -15,6 +15,7 @@ const CANONICAL: Record<ItemType, string> = {
   tasks: 'TASK.md',
   processes: 'PROCESS.md',
   extensions: 'index.ts',
+  agents: 'AGENT.md',
 };
 
 function countItems(type: ItemType): number {