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__/pty-attach.test.js

@@ -69,6 +69,33 @@ describe("pty-attach", () => {
     assert.deepEqual(calls[0], ["set-option", "-t", "=agenthub-lane-1:", "mouse", "on"]);
   });
 
+  it("attaches with the RUNNING tmux server's own binary, not the one on PATH", () => {
+    // A tmux upgraded while its server runs leaves a newer client on PATH that
+    // the old server answers with "open terminal failed: not a terminal".
+    tmux.__setExecImpl((args) => (args[0] === "display-message" ? `${process.pid}\n` : ""));
+    let file;
+    ptyAttach.__setSpawnImpl((f) => {
+      file = f;
+      return fakePty;
+    });
+    ptyAttach.attach(makeFakeWs(), "agenthub-lane-1", { cols: 80, rows: 24 });
+    assert.equal(file, process.platform === "linux" ? `/proc/${process.pid}/exe` : "tmux");
+  });
+
+  it("falls back to tmux on PATH when the server's pid cannot be read", () => {
+    tmux.__setExecImpl((args) => {
+      if (args[0] === "display-message") throw new Error("no server running");
+      return "";
+    });
+    let file;
+    ptyAttach.__setSpawnImpl((f) => {
+      file = f;
+      return fakePty;
+    });
+    ptyAttach.attach(makeFakeWs(), "agenthub-lane-1", { cols: 80, rows: 24 });
+    assert.equal(file, "tmux");
+  });
+
   it("still attaches even if the mouse-mode set-option call fails", () => {
     tmux.__setExecImpl(() => {
       throw new Error("no such session: agenthub-lane-1");