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/pages/Sessions.tsx

@@ -304,6 +304,9 @@ export function Sessions({ embedded = false }: { embedded?: boolean } = {}) {
           ]),
           "text/csv"
         );
+      // The server answers at most 10 000 rows: say the file is not all of them.
+      if (res.total > res.sessions.length)
+        toast.info(t("exportCapped", { shown: res.sessions.length, total: res.total }));
     } catch (err) {
       toast.error(err);
     } finally {