feat(settings): data-safe editors, deep-linked search, Data/About/Cost pages

- EditorModal loads once per path (a parent re-render no longer reloads the
  file over the user's typing), refuses Save after a failed load, opens a
  truncated (>256 KB) file read-only, and asks before overwriting a file
  that changed on disk or could not be re-read.
- Settings/Hooks editors unset only keys from the snapshot taken at Edit,
  warn when the file changed underneath, keep a renamed key's value, and
  refuse a new key named like a redacted one (env) or a read-only hook
  event, which used to replace the secret/hooks.
- Project scope shows its resolved folder and is disabled inside the
  plugin cache. Account-profile, pricing-row and pet deletes confirm;
  two-click actions disarm after 3 s; unsaved drafts ask before closing.
- Search indexes every Claude Code / Codex sub-tab, opens it via ?tab= and
  scrolls to + highlights the row; the active config tab is in the URL.
- General splits into General / Data / About; Pricing moves to a Cost
  group with one shared load; config tabs group as Content / Extensions /
  Config with arrow-key roving; Promise.allSettled per tab.
- Data: browser-preferences export/import (allowlisted keys), per-section
  reset, housekeeping dry-run first, clear-all behind a typed phrase.
  Server: purge days must be a whole number >= 1 (INVALID_PURGE_DAYS) and
  dry_run returns exactly what the real run would delete.
- Alerts can be edited; webhooks/alerts/remote-source failures toast;
  copies go through copyText; modals get dialog roles and useDialog.
- Sagi: Ctrl/Cmd+B only when shown and not typing, default spot clear of
  row controls, arrow keys move it, reduced motion honoured; the dead
  /run launch link goes to the workspace.

client/src/lib/__tests__/prefsBackup.test.ts

@@ -0,0 +1,43 @@
+/**
+ * @file Tests for the browser-preferences backup: only allowlisted keys leave
+ * (never the access token), an import writes only allowlisted keys, and a file
+ * that is not one of ours is refused.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+
+import { beforeEach, describe, expect, it } from "vitest";
+import { exportPrefs, importPrefs, PREFS_FORMAT } from "../prefsBackup";
+
+beforeEach(() => localStorage.clear());
+
+describe("prefsBackup", () => {
+  it("exports only preference keys, never the access token", () => {
+    localStorage.setItem("theme", "dark");
+    localStorage.setItem("agenthub.pet.size", "2");
+    localStorage.setItem("agent-monitor-notifications", "{}");
+    localStorage.setItem("dashboard_token", "secret");
+    localStorage.setItem("sidebar-connection-stats", "{}");
+    const out = exportPrefs();
+    expect(out.format).toBe(PREFS_FORMAT);
+    expect(Object.keys(out.prefs).sort()).toEqual([
+      "agent-monitor-notifications",
+      "agenthub.pet.size",
+      "theme",
+    ]);
+  });
+
+  it("imports allowlisted keys only and refuses a foreign file", () => {
+    const n = importPrefs(
+      JSON.stringify({
+        format: PREFS_FORMAT,
+        version: 1,
+        prefs: { theme: "light", dashboard_token: "evil", "agenthub.x": 5 },
+      })
+    );
+    expect(n).toBe(1);
+    expect(localStorage.getItem("theme")).toBe("light");
+    expect(localStorage.getItem("dashboard_token")).toBeNull();
+    expect(() => importPrefs(JSON.stringify({ format: "other", prefs: {} }))).toThrow();
+    expect(() => importPrefs("not json")).toThrow();
+  });
+});