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

client/src/i18n/locales/en/sessions.json

@@ -56,6 +56,7 @@
   },
   "exportCsv": "CSV",
   "exportJson": "JSON",
+  "exportCapped": "The file holds {{shown}} of {{total}} sessions (the export limit) — narrow the filters to export the rest.",
   "filterDirectory": "Filter by directory",
   "allDirectories": "All directories",
   "sortLabel": "Sort sessions",