feat: Claude Code Monitor — lanes, pipelines and a merged workspace

Internal SmartGift build of a Claude Code monitoring dashboard.

Lanes: a durable unit of parallel agent work, one per working directory,
tracked across session restarts. Managed lanes are git worktrees the
dashboard provisions and can reset or remove behind a three-check destroy
guard and a counted preflight; adopted lanes are directories you already
own and are never destroyable.

Pipelines: a lane moves through pipeline stages. A stage the agent declares
with evidence renders green; a stage inferred from the tool-event stream
renders dashed amber and never counts as done. Detection is forward-only
within a 30-minute window, and never writes the declared stage.

Workspace: one page at /run with a lane grid, the selected lane's pipeline,
and a full Claude console behind a disclosure.

client/src/hooks/useDocumentTitle.ts

@@ -0,0 +1,25 @@
+/**
+ * @file useDocumentTitle.ts
+ * @description Sets `document.title` for the current route/page and restores the
+ * previous title on unmount so browser tabs stay distinguishable.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { useEffect } from "react";
+
+const APP_SUFFIX = "Claude Code Agent Monitor";
+
+/**
+ * Update the browser tab title while this component is mounted.
+ * @param title Page-specific title segment (without the app suffix), or null to skip.
+ */
+export function useDocumentTitle(title: string | null | undefined): void {
+  useEffect(() => {
+    if (!title) return;
+    const previous = document.title;
+    document.title = `${title} · ${APP_SUFFIX}`;
+    return () => {
+      document.title = previous;
+    };
+  }, [title]);
+}