fix: event-loop freezes, plugin-install boot crash, tmux attach/scrollbar, Codex transcripts

- GET /api/workflows: one LEAD() window pass in a read worker (read-pool.js,
  workflow-stats.js); idx_events_session restored, idx_events_tool added
- compat-sqlite gains function/pluck/readonly so a plugin install without a
  better-sqlite3 build boots again; antigravity-usage uses db.js's Database
- install-hooks adds no checkout hooks while the agenthub plugin is enabled
  (events were doubled)
- terminal attach runs the live tmux server's own binary; the pane scrollbar
  gets a visible 2-column style, and claude panes start with
  CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1 so tmux keeps history to scroll
- Codex sessions' conversation in GET /api/sessions/:id/transcript
- Codex/Antigravity sessions claimed by their workspace without hooks
- UI-audit follow-ups, docs and OpenAPI

server/__tests__/api.test.js

@@ -1813,10 +1813,10 @@ describe("Database Integrity", () => {
 
     assert.ok(indexes.includes("idx_agents_session"));
     assert.ok(indexes.includes("idx_agents_status"));
-    // (session_id, created_at) replaces the bare session_id index, a prefix of
-    // idx_events_session_type that only cost disk.
+    // (session_id, id) is NOT a prefix of idx_events_session_type: the hook
+    // duplicate guard reads a session's latest event by id through it.
     assert.ok(indexes.includes("idx_events_session_created"));
-    assert.ok(!indexes.includes("idx_events_session"));
+    assert.ok(indexes.includes("idx_events_session"));
     assert.ok(indexes.includes("idx_events_type"));
     assert.ok(indexes.includes("idx_events_created"));
     assert.ok(indexes.includes("idx_sessions_status"));