test(e2e): expand coverage and harden cross-file isolation

New specs (4):
- accept-invite: pre-registrant flow happy path + cadence/preset UX
- admin-pre-registrants: list, filter, action gating, redirect
- admin-series: list, create, edit (delete skipped — button no-ops)
- admin-site-content: list whitelist, edit + roundtrip on /

Extended specs (6):
- join-flow: cadence ×12 math, guidance label, paid-tier success
- events: series-pass-required, member-savings gating
- admin-events: full CRUD via /admin/events/create?edit=<id>
- admin-members: add-member submit, status select, detail nav
- a11y: add /accept-invite, /member/account, /board, /admin/pre-registrants
- wave-slack-onboarding: 9 of 16 scaffold tests now passing

Cross-file isolation hardening:
- admin-events CRUD: refresh auth cookie (auth.spec.js logout test
  bumps tokenVersion on the shared admin), wait for hydration
  before form fill, search by unique title to dodge pagination.
- board: switch memberPage from shared admin to dedicated seeded
  member to avoid the same tokenVersion race.
- wave-slack §6.4: create dedicated test member, filter by email
  before clicking, removing the "first row" anchor.

Also fixed board heading drift ("Board" → "Bulletin Board").

e2e/admin-events.spec.js

@@ -53,3 +53,116 @@ test.describe('Admin events access control', () => {
     expect(page.url()).not.toContain('/admin/events')
   })
 })
+
+test.describe('Admin events CRUD', () => {
+  test('create, edit, and delete an event', async ({ adminPage }) => {
+    const suffix = Date.now().toString().slice(-6)
+    const title = `e2e-event-${suffix}`
+    const editedTitle = `e2e-event-${suffix}-edited`
+
+    // Re-prime the auth cookie immediately before this multi-step flow.
+    // The shared test-admin account's tokenVersion is bumped whenever
+    // auth.spec.js's logout test runs in parallel, which would otherwise
+    // surface mid-flow as "Session has been revoked" on the first POST.
+    const loginRes = await adminPage.context().request.get('/api/dev/test-login', { maxRedirects: 0 })
+    if (loginRes.status() !== 302) {
+      throw new Error(`Failed to refresh admin session: ${loginRes.status()}`)
+    }
+
+    // --- Create ---
+    await adminPage.goto('/admin/events/create')
+    await expect(adminPage.locator('h1')).toContainText('Create Event')
+    // Ensure Vue has hydrated (initial $fetch for series/tags has resolved)
+    // before interacting — under cross-file load, hydration can lag and a
+    // pre-hydration submit will native-POST against an empty form.
+    await adminPage.waitForLoadState('networkidle')
+
+    await adminPage
+      .getByPlaceholder('Enter a clear, descriptive event title')
+      .fill(title)
+
+    await adminPage
+      .getByPlaceholder(
+        'Provide a clear description of what attendees can expect from this event'
+      )
+      .fill('e2e test event description')
+
+    await adminPage
+      .getByPlaceholder('e.g., https://zoom.us/j/123... or #channel-name')
+      .fill('https://example.com/zoom')
+
+    const startInput = adminPage.getByPlaceholder(
+      "e.g., 'tomorrow at 3pm', 'next Friday at 9am'"
+    )
+    await startInput.fill('next Tuesday at 3pm')
+    await startInput.blur()
+
+    const endInput = adminPage.getByPlaceholder(
+      "e.g., 'tomorrow at 5pm', 'next Friday at 11am'"
+    )
+    await endInput.fill('next Tuesday at 5pm')
+    await endInput.blur()
+
+    await adminPage.getByRole('button', { name: 'Create Event' }).click()
+
+    // The form posts via $fetch and then auto-redirects after a 1.5s setTimeout.
+    // Under cross-file load that auto-redirect can race against waitForURL.
+    // Wait for the surfaced success/error state, fail fast on error, then
+    // navigate explicitly so subsequent assertions are deterministic.
+    await expect(
+      adminPage.locator('.success-box').or(adminPage.locator('.error-box'))
+    ).toBeVisible({ timeout: 15000 })
+    await expect(adminPage.locator('.success-box')).toBeVisible()
+    await adminPage.goto('/admin/events')
+    await adminPage.waitForLoadState('networkidle')
+
+    // Filter to just our event — orphan rows from prior failed runs can push
+    // the new row off page 1 of the paginated list.
+    await adminPage.getByPlaceholder('Search events...').fill(title)
+    const row = adminPage.locator('tr', { hasText: title })
+    await expect(row).toBeVisible({ timeout: 10000 })
+
+    // --- Edit ---
+    // Find the event ID from the row's "View" link (href is /events/<slug-or-id>),
+    // and use the row's Edit button. Pair the click with waitForURL so we don't
+    // miss the navigation event under load.
+    await Promise.all([
+      adminPage.waitForURL(/\/admin\/events\/create\?edit=/, { timeout: 15000 }),
+      row.getByRole('button', { name: 'Edit' }).click(),
+    ])
+    await expect(adminPage.locator('h1')).toContainText('Edit Event')
+
+    const titleInput = adminPage.getByPlaceholder(
+      'Enter a clear, descriptive event title'
+    )
+    await titleInput.fill(editedTitle)
+
+    await adminPage.getByRole('button', { name: 'Update Event' }).click()
+
+    await expect(
+      adminPage.locator('.success-box').or(adminPage.locator('.error-box'))
+    ).toBeVisible({ timeout: 15000 })
+    await expect(adminPage.locator('.success-box')).toBeVisible()
+    await adminPage.goto('/admin/events')
+    await adminPage.waitForLoadState('networkidle')
+
+    // Filter to the edited event's unique title for the same pagination reason.
+    await adminPage.getByPlaceholder('Search events...').fill(editedTitle)
+    const editedRow = adminPage.locator('tr', { hasText: editedTitle })
+    await expect(editedRow).toBeVisible({ timeout: 10000 })
+
+    // --- Delete (custom modal, not browser dialog) ---
+    await editedRow.getByRole('button', { name: 'Del' }).click()
+    await expect(
+      adminPage.getByRole('heading', { name: 'Delete Event' })
+    ).toBeVisible()
+    await adminPage
+      .locator('.modal')
+      .getByRole('button', { name: 'Delete' })
+      .click()
+
+    await expect(
+      adminPage.locator('tr', { hasText: editedTitle })
+    ).toHaveCount(0, { timeout: 10000 })
+  })
+})