fix: email verification flow and trial system

Backend fixes:
- Fixed timezone-aware datetime comparison in verify_email endpoint
- Added trial_ends_at (14 days) for new registrations
- All datetime.now() calls now use timezone.utc

Frontend additions:
- Added EmailVerificationBanner component for unverified users
- Banner shows warning before trial banner in Dashboard
- Clear messaging about verification requirement

This fixes the 500 error on email verification and ensures new users
see both verification and trial status correctly.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/routers/auth.py

@@ -7,7 +7,7 @@ import os
 import secrets
 import smtplib
 from typing import Optional
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from email.mime.text import MIMEText
 
 from fastapi import APIRouter, HTTPException, Header, Depends
@@ -233,19 +233,20 @@ async def register(req: RegisterRequest, request: Request):
 
         # Generate verification token
         verification_token = secrets.token_urlsafe(32)
-        verification_expires = datetime.now() + timedelta(hours=24)
+        verification_expires = datetime.now(timezone.utc) + timedelta(hours=24)
 
         # Create profile (inactive until verified)
         profile_id = str(secrets.token_hex(16))
         pin_hash = hash_pin(password)
+        trial_ends = datetime.now(timezone.utc) + timedelta(days=14)  # 14-day trial
 
         cur.execute("""
             INSERT INTO profiles (
                 id, name, email, pin_hash, auth_type, role, tier,
                 email_verified, verification_token, verification_expires,
-                created
-            ) VALUES (%s, %s, %s, %s, 'email', 'user', 'free', FALSE, %s, %s, CURRENT_TIMESTAMP)
-        """, (profile_id, name, email, pin_hash, verification_token, verification_expires))
+                trial_ends_at, created
+            ) VALUES (%s, %s, %s, %s, 'email', 'user', 'free', FALSE, %s, %s, %s, CURRENT_TIMESTAMP)
+        """, (profile_id, name, email, pin_hash, verification_token, verification_expires, trial_ends))
 
     # Send verification email
     app_url = os.getenv("APP_URL", "https://mitai.jinkendo.de")
@@ -294,7 +295,7 @@ async def verify_email(token: str):
             raise HTTPException(400, "E-Mail-Adresse bereits bestätigt")
 
         # Check if token expired
-        if prof['verification_expires'] and datetime.now() > prof['verification_expires']:
+        if prof['verification_expires'] and datetime.now(timezone.utc) > prof['verification_expires']:
             raise HTTPException(400, "Verifikations-Link abgelaufen. Bitte registriere dich erneut.")
 
         # Mark as verified and clear token
@@ -306,7 +307,7 @@ async def verify_email(token: str):
 
         # Create session (auto-login after verification)
         session_token = make_token()
-        expires = datetime.now() + timedelta(days=30)
+        expires = datetime.now(timezone.utc) + timedelta(days=30)
         cur.execute("""
             INSERT INTO sessions (token, profile_id, expires_at, created)
             VALUES (%s, %s, %s, CURRENT_TIMESTAMP)

frontend/src/components/EmailVerificationBanner.jsx

@@ -0,0 +1,42 @@
+export default function EmailVerificationBanner({ profile }) {
+  // Only show if email is not verified
+  if (!profile || profile.email_verified !== false) return null
+
+  return (
+    <div style={{
+      background: '#FFF4E6',
+      border: '2px solid #F59E0B',
+      borderRadius: 12,
+      padding: '16px 20px',
+      marginBottom: 20,
+      display: 'flex',
+      alignItems: 'center',
+      gap: 16
+    }}>
+      <div style={{
+        fontSize: 32,
+        lineHeight: 1
+      }}>
+        📧
+      </div>
+      <div style={{flex: 1}}>
+        <div style={{
+          fontWeight: 700,
+          fontSize: 15,
+          color: '#D97706',
+          marginBottom: 4
+        }}>
+          E-Mail-Adresse noch nicht bestätigt
+        </div>
+        <div style={{
+          fontSize: 13,
+          color: 'var(--text2)',
+          lineHeight: 1.4
+        }}>
+          Bitte prüfe dein Postfach und klicke auf den Bestätigungslink.
+          Ohne Bestätigung ist dein Account eingeschränkt.
+        </div>
+      </div>
+    </div>
+  )
+}

frontend/src/pages/Dashboard.jsx

@@ -9,6 +9,7 @@ import { api } from '../utils/api'
 import { useProfile } from '../context/ProfileContext'
 import { getBfCategory } from '../utils/calc'
 import TrialBanner from '../components/TrialBanner'
+import EmailVerificationBanner from '../components/EmailVerificationBanner'
 import { getInterpretation, getStatusColor, getStatusBg } from '../utils/interpret'
 import Markdown from '../utils/Markdown'
 import dayjs from 'dayjs'
@@ -316,6 +317,9 @@ export default function Dashboard() {
         </div>
       </div>
 
+      {/* Email Verification Banner */}
+      <EmailVerificationBanner profile={activeProfile}/>
+
       {/* Trial Banner */}
       <TrialBanner profile={activeProfile}/>