test(e2e): align specs with current page structure

join-flow:
- Form now requires Community Guidelines agreement; tests check the
  checkbox before expecting submit to enable.
- Contribution input is a numeric field with preset chip buttons, not a
  USelect with $0/mo options — fill the input directly.
- Success state lives in SignupFlowOverlay ("Welcome to Ghost Guild!");
  no .success-box exists. Match by heading instead.
- Inline .error-box renders OUTSIDE <form>, so duplicate-email assertion
  uses .signup-flow-overlay .error-box (which is the user-facing error).

member-profile:
- "How you appear to other members" copy was retired; replace with the
  stable "Show in Member Directory" structural label.
- Add waitForLoadState('networkidle') after goto for ClientOnly auth
  hydration so "Edit Profile" reliably appears within timeout.

board:
- Add waitForLoadState('networkidle') after goto so the action-bar's
  "+ New Post" click handler is bound before the test clicks.
- Submit button is named exactly "Post" — disambiguate from "+ New Post"
  buttons with { exact: true }.
- Delete is a two-step in-card confirm (Delete → Confirm), not a native
  browser dialog; drop the page.once('dialog') listener.

admin-board-channels:
- Channel name placeholder is "e.g., coop-formation" (no leading #).
- Slack Channel ID input only appears in the Edit modal (v-if="editingId"),
  not on Create — Slack channel is auto-created server-side. Drop the
  slack ID fill from the Create step.
- Add waitForLoadState('networkidle') before opening the modal.

e2e/admin-board-channels.spec.js

@@ -11,6 +11,7 @@ test.describe('Admin board channels page', () => {
 
   test('create, edit, and delete a channel', async ({ adminPage }) => {
     await adminPage.goto('/admin/board-channels')
+    await adminPage.waitForLoadState('networkidle')
     await expect(adminPage.getByRole('heading', { name: 'Board Channels' })).toBeVisible({
       timeout: 15000,
     })
@@ -18,14 +19,14 @@ test.describe('Admin board channels page', () => {
     const suffix = Date.now().toString().slice(-6)
     const channelName = `e2e-channel-${suffix}`
     const editedName = `e2e-channel-${suffix}-edited`
-    const slackId = `C${suffix}XYZ`
 
     // --- Create ---
+    // Create flow only takes a name; the Slack channel ID is auto-assigned on
+    // creation and only becomes editable in the Edit modal.
     await adminPage.getByRole('button', { name: '+ New Channel' }).click()
     await expect(adminPage.getByRole('heading', { name: 'New Channel' })).toBeVisible()
 
-    await adminPage.locator('input[placeholder="e.g., #coop-formation"]').fill(channelName)
-    await adminPage.locator('input[placeholder="C0123456789"]').fill(slackId)
+    await adminPage.locator('input[placeholder="e.g., coop-formation"]').fill(channelName)
 
     // Select the first available cooperative tag if any are present
     const firstTagCheckbox = adminPage.locator('.tag-select input[type="checkbox"]').first()
@@ -44,7 +45,7 @@ test.describe('Admin board channels page', () => {
     await row.getByRole('button', { name: 'Edit' }).click()
 
     await expect(adminPage.getByRole('heading', { name: 'Edit Channel' })).toBeVisible()
-    const nameInput = adminPage.locator('input[placeholder="e.g., #coop-formation"]')
+    const nameInput = adminPage.locator('input[placeholder="e.g., coop-formation"]')
     await nameInput.fill(editedName)
     await adminPage.getByRole('button', { name: 'Save Changes' }).click()