Redesign profile photo upload with circular crop UI, server-side processing, and form integration

- Replace square preview with 280x280 circular container with crop ring overlay
- Zoom slider and drag-to-pan for precise crop positioning
- Client-side crop via canvas at 400x400 output resolution
- Server-side resize to 400x400 (LANCZOS), EXIF stripping, RGB conversion, JPEG optimization
- Generate CSRF token in before_request so photo upload fetch works
- Save button now also submits the profile form (photo + fields updated together)
- Remove dead photo-upload-form handler and unused CSS
- Clean up debug markers and attendee code field from profile page

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

app.py

@@ -610,6 +610,10 @@ def before_request():
         if lang in SUPPORTED_LOCALES:
             session['locale'] = lang
 
+    # Ensure CSRF token exists for all state-changing requests
+    if 'csrf_token' not in session:
+        session['csrf_token'] = secrets.token_hex(32)
+
     # CSRF validation for state-changing requests
     if request.method in ('POST', 'PUT', 'DELETE', 'PATCH'):
         # Skip CSRF for login (users don't have a session yet)
@@ -5332,7 +5336,7 @@ def staff_profile():
 @app.route('/attendee/photo', methods=['POST'])
 @login_required
 def upload_photo():
-    """Upload profile photo."""
+    """Upload and process profile photo (resize, strip EXIF, optimize)."""
     if session.get('user_type') != 'attendee':
         return jsonify({'error': 'Access denied'}), 403
 
@@ -5343,44 +5347,65 @@ def upload_photo():
     if file.filename == '':
         return jsonify({'error': 'No file selected'}), 400
 
-    if file and allowed_file(file.filename):
-        # Read file content for validation
-        file_content = file.read()
-        try:
-            from PIL import Image
-            img = Image.open(io.BytesIO(file_content))
-            img.verify()
-        except Exception:
-            return jsonify({'error': 'Invalid image file'}), 400
+    if not (file and allowed_file(file.filename)):
+        return jsonify({'error': 'Invalid file type'}), 400
 
-        # Generate unique filename
-        ext = file.filename.rsplit('.', 1)[1].lower()
-        filename = f"{uuid.uuid4()}.{ext}"
-        filepath = os.path.join(app.config['UPLOAD_FOLDER'], filename)
+    file_content = file.read()
 
-        # Delete old photo if exists
-        conn = get_db_connection()
-        cursor = conn.cursor(dictionary=True)
-        cursor.execute("SELECT profile_picture FROM attendees WHERE id = %s", (session['user_id'],))
-        row = cursor.fetchone()
-        old_photo = row['profile_picture'] if row else None
-        if old_photo:
-            old_path = os.path.join(app.config['UPLOAD_FOLDER'], old_photo)
-            if os.path.exists(old_path):
-                os.remove(old_path)
+    # Process image: validate, resize, strip EXIF, optimize
+    try:
+        from PIL import Image
+        img = Image.open(io.BytesIO(file_content))
+        img.verify()
+        # Re-open after verify() — verify() consumes the image
+        img = Image.open(io.BytesIO(file_content))
+    except Exception:
+        return jsonify({'error': 'Invalid image file'}), 400
 
-        # Save the file
-        with open(filepath, 'wb') as f:
-            f.write(file_content)
+    try:
+        # Convert to RGB (handles RGBA PNG, CMYK, etc.)
+        if img.mode in ('RGBA', 'P', 'LA', 'CMYK'):
+            img = img.convert('RGB')
 
-        cursor.execute("UPDATE attendees SET profile_picture = %s WHERE id = %s", (filename, session['user_id']))
-        conn.commit()
-        cursor.close()
-        conn.close()
+        # Resize to standard dimensions
+        img = img.resize((400, 400), Image.LANCZOS)
 
-        return jsonify({'success': True, 'filename': filename})
+        # Strip EXIF data for privacy
+        from PIL import ImageOps
+        img = ImageOps.exif_transpose(img)
 
-    return jsonify({'error': 'Invalid file type'}), 400
+        # Save as optimized JPEG, no EXIF
+        output = io.BytesIO()
+        img.save(output, format='JPEG', quality=85, optimize=True)
+        output.seek(0)
+        processed_content = output.read()
+    except Exception:
+        return jsonify({'error': 'Failed to process image'}), 500
+
+    # Always save as .jpg since we convert to JPEG
+    filename = f"{uuid.uuid4()}.jpg"
+    filepath = os.path.join(app.config['UPLOAD_FOLDER'], filename)
+
+    # Delete old photo if exists
+    conn = get_db_connection()
+    cursor = conn.cursor(dictionary=True)
+    cursor.execute("SELECT profile_picture FROM attendees WHERE id = %s", (session['user_id'],))
+    row = cursor.fetchone()
+    old_photo = row['profile_picture'] if row else None
+    if old_photo:
+        old_path = os.path.join(app.config['UPLOAD_FOLDER'], old_photo)
+        if os.path.exists(old_path):
+            os.remove(old_path)
+
+    with open(filepath, 'wb') as f:
+        f.write(processed_content)
+
+    cursor.execute("UPDATE attendees SET profile_picture = %s WHERE id = %s", (filename, session['user_id']))
+    conn.commit()
+    cursor.close()
+    conn.close()
+
+    return jsonify({'success': True, 'filename': filename})
 
 
 # Routes - Attendees list and connections