Add stage 7: email verification magic links and a profile page

Backend
- New Mail namespace: a Mailer interface with SMTP (phpmailer), PHP mail()
  (the default fallback), and log-to-file transports, selected by
  MAIL_TRANSPORT. EmailVerifier issues a hashed, 15-minute magic-link token
  and sends the link (APP_URL/verify-email?token=...).
- Migration 005: email_verifications table + users.verification_email_sent_at.
- Registration now emails a verification link (best effort — a send failure
  doesn't fail registration).
- POST /api/auth/verify-email consumes a token and returns a session, so
  opening the link verifies the address (or applies a pending email change)
  and logs the user in. Single-use; distinct 400s for invalid/used/expired.
- POST /api/email/verification resends; POST /api/email/change requests a
  deferred change (current password required; link goes to the new address;
  users.email only updates when that link is opened). Both throttled to once
  per 60s, returning 429 + retry_after.
- GET /api/me and every session payload now include pending_email. Shared
  SessionPayload builds the user/session JSON for all entry points.

Frontend
- /verify-email view: posts the token, adopts the returned session, redirects.
- /profile view: shows address + status, a resend button with a live cooldown
  (driven by retry_after / 429), and a change-email form (new address +
  current password) that surfaces the pending change.
- Header shows a "verify email" badge linking to the profile.

Tests: 9 new (EmailVerificationTest) covering the link lifecycle, throttle,
and deferred change; AuthTest folded into ApiTestCase, which now routes mail
to a per-test log. Suite: 32 passing.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/Support/MailConfig.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Support;
+
+/**
+ * Mail delivery settings.
+ *
+ * `transport`:
+ *   - "mail" (default) — PHP's built-in mail() function
+ *   - "smtp"           — an SMTP server (host/port/credentials below)
+ *   - "log"            — append messages to `logPath` instead of sending (dev/test)
+ */
+final class MailConfig
+{
+    public function __construct(
+        public readonly string $transport,
+        public readonly string $fromAddress,
+        public readonly string $fromName,
+        public readonly string $logPath,
+        public readonly ?string $smtpHost,
+        public readonly int $smtpPort,
+        public readonly ?string $smtpUsername,
+        public readonly ?string $smtpPassword,
+        public readonly string $smtpEncryption,
+    ) {
+    }
+}