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/components/__tests__/WorkspaceTree.test.tsx

@@ -154,12 +154,32 @@ describe("WorkspaceTree", () => {
     expect(within(list).getByText("Live one")).toBeInTheDocument();
     // Its OWN sessions only — never the rest of its folder.
     expect(api.sessions.list).toHaveBeenCalledTimes(1);
-    expect(api.sessions.list).toHaveBeenCalledWith({ lane: 1, archived: false, limit: 20 });
+    expect(api.sessions.list).toHaveBeenCalledWith({ lane: 1, archived: false, limit: 6 });
     expect(JSON.parse(localStorage.getItem("agenthub.sidebar.projects")!).expanded).toEqual({
       "1": true,
     });
   });
 
+  it("shows six sessions and loads the rest on See all", async () => {
+    const all = Array.from({ length: 9 }, (_, i) => session(`s-${i}`, `Session ${i}`));
+    vi.mocked(api.sessions.list).mockImplementation(async (p) => ({
+      sessions: all.slice(0, p?.limit),
+      total: all.length,
+      limit: p?.limit ?? 50,
+      offset: 0,
+    }));
+    const user = userEvent.setup();
+    renderTree();
+    await user.click(await screen.findByTestId("workspace-toggle-1"));
+    const list = await screen.findByTestId("workspace-sessions-1");
+    expect(within(list).getAllByTestId(/^workspace-session-s-\d+$/)).toHaveLength(6);
+    expect(screen.getByTestId("workspace-sessions-more-1")).toHaveTextContent("See all (3 more)");
+    await user.click(screen.getByTestId("workspace-sessions-more-1"));
+    expect(api.sessions.list).toHaveBeenLastCalledWith({ lane: 1, archived: false, limit: 9 });
+    await screen.findByText("Session 8");
+    expect(screen.queryByTestId("workspace-sessions-more-1")).toBeNull();
+  });
+
   it("renames a session on double-click + Enter, and archives one from its row", async () => {
     const user = userEvent.setup();
     renderTree();