Read Recent updates afresh per opening and guard their URLs by origin

Address the review of PR #176 (Feature 21, task 96e2dc3f):

- MQ-176-01: useUpdates drops its list as soon as the sheet closes
  (gcTime 0), so each opening reads GET /api/v1/updates afresh and only
  marks seen through the newest of that read, never a cached list.
- MQ-176-02: parseUpdate checks each url with appPath from
  push/notification.ts, by parsed origin, instead of a prefix check that
  tabs and newlines got past; the url kept is the path as parsed.
- MQ-176-03: TestMarkUpdatesSeen asserts updated_at is kept and settings
  subscribers are not told.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/home/api.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it } from 'vitest'
+import { parseUpdates } from './api.ts'
+
+const origin = 'https://mealquest.example'
+const where = 'GET /api/v1/updates'
+
+// body is a GET /api/v1/updates body holding one update that opens url.
+function body(url: string) {
+  return {
+    updates: [{ type: 'plan_ready', title: 'Your week is drafted', body: '', url, created_at: '2026-10-10T16:00:00.000Z' }],
+  }
+}
+
+describe('parseUpdates', () => {
+  it('keeps a same-origin path with its query and fragment, as parsed', () => {
+    expect(parseUpdates(where, body('/plan/shopping?week=2026-10-05#tuesday'), origin)[0]!.url).toBe(
+      '/plan/shopping?week=2026-10-05#tuesday',
+    )
+    expect(parseUpdates(where, body('/plan/../discover'), origin)[0]!.url).toBe('/discover')
+  })
+
+  // Each of these would open another site, or run script, once parsed: URL
+  // parsing strips tabs and newlines and reads a backslash as a slash.
+  it.each([
+    ['a tab', '/\t/evil.example/x'],
+    ['a newline', '/\n/evil.example/x'],
+    ['a carriage return', '/\r/evil.example/x'],
+    ['a backslash', '/\\evil.example/x'],
+    ['dot segments', '/..//evil.example/x'],
+    ['a protocol-relative URL', '//evil.example/x'],
+    ['an absolute URL', 'https://evil.example/x'],
+    ['javascript:', 'javascript:alert(1)'],
+    ['a relative path', 'plan'],
+  ])('refuses an update url with %s', (_, url) => {
+    expect(() => parseUpdates(where, body(url), origin)).toThrow(
+      `${where}: update url ${JSON.stringify(url)} is not a path on this app`,
+    )
+  })
+})