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/lib/toast.ts

@@ -16,6 +16,7 @@ export interface ToastItem {
 }
 
 const SUCCESS_MS = 4000;
+const MAX_TOASTS = 4;
 let items: ToastItem[] = [];
 let nextId = 1;
 const listeners = new Set<(items: ToastItem[]) => void>();
@@ -33,7 +34,14 @@ export function dismissToast(id: number): void {
 function push(kind: ToastKind, message: string): number {
   const id = nextId++;
   // Same text twice in a row (a double click, a retry) shows once.
-  items = [...items.filter((t) => t.message !== message), { id, kind, message }].slice(-4);
+  const next = [...items.filter((t) => t.message !== message), { id, kind, message }];
+  // Over four: the oldest non-error goes first, so an unread error is not pushed
+  // out by a few copies or saves; the newest toast always stays.
+  while (next.length > MAX_TOASTS) {
+    const older = next.slice(0, -1).findIndex((t) => t.kind !== "error");
+    next.splice(older === -1 ? 0 : older, 1);
+  }
+  items = next;
   emit();
   if (kind !== "error") window.setTimeout(() => dismissToast(id), SUCCESS_MS);
   return id;