feat: v2.5.4 — Query Explorer folded into Sessions, Windows picker and paths

- Sessions page tabs: Sessions · Events · Agents. QueryExplorer.tsx became
  AgentsTable.tsx (agents only — sessions and events already had tabs);
  /query redirects to /sessions?view=agents and leaves the sidebar.
  GET /api/query is unchanged and still answers all three entities.
- Windows picker opens in front: -EncodedCommand script spends the hidden
  first ShowWindow that windowsHide gives the process, then brings the TopMost
  owner forward via AttachThreadInput (v2.5.3's owner was itself hidden).
- Session page Resume/Fork/Open pane: owningLane and sessionWorktreeName
  match Windows folders (either separator), with a test.

docs/API.md

@@ -2531,6 +2531,8 @@ A snapshot freezes a session as it is at that moment into one immutable `session
 
 ### Query Explorer
 
+The dashboard's Sessions page reads its **Agents** tab (`/sessions?view=agents`; the old `/query` page redirects there) from `entity=agents`; sessions and events have their own tabs over `GET /api/sessions` and `GET /api/events`. The route still answers all three entities for scripts and exports.
+
 ```http
 GET /api/query?entity=sessions|events|agents&q=&tool=&status=&cwd=&from=&to=&tz_offset=&sources=&sort=&dir=asc|desc&limit=&offset=&format=csv|json
 ```