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/SettingsHub.tsx

@@ -96,6 +96,14 @@ const historyIdx = (): number => {
   return typeof idx === "number" ? idx : 0;
 };
 
+/**
+ * How far Back moves: to the entry before the one Settings was entered at, and
+ * always at least one step — after a browser Back below that entry, the plain
+ * difference would be 0 (`history.go(0)`, a reload) or a step forward.
+ */
+export const backDelta = (current: number, entry: number): number =>
+  -Math.max(1, current - entry + 1);
+
 /** An unknown section: say so, then show General. */
 function UnknownSection({ name }: { name: string }) {
   const { t } = useTranslation("settings");
@@ -142,7 +150,12 @@ export function SettingsHub() {
   // Deep link to a row: scroll to the anchor once the page has rendered it
   // (content loads async, so poll briefly) and highlight it for a moment.
   useEffect(() => {
-    const id = decodeURIComponent(location.hash.slice(1));
+    let id = location.hash.slice(1);
+    try {
+      id = decodeURIComponent(id);
+    } catch {
+      // A malformed escape (`#%`): look the raw text up instead of crashing.
+    }
     if (!id) return;
     let timer: number | undefined;
     let lit: Element | null = null;
@@ -363,7 +376,7 @@ export function SettingsHub() {
   const back = (e: MouseEvent) => {
     if (!canGoBack) return;
     e.preventDefault();
-    navigate(-(historyIdx() - (entryIdx.current ?? 0) + 1));
+    navigate(backDelta(historyIdx(), entryIdx.current ?? 0));
   };
 
   return (