Add middleware to allow mobile app iframe embedding

Created Django middleware that detects requests from the KeepItGoing
mobile app (via User-Agent) and removes X-Frame-Options header to
allow iframe embedding.

Changes:
- Created tasks/middleware/mobile_app.py with AllowMobileAppFramingMiddleware
- Added middleware to settings after XFrameOptionsMiddleware
- Detects Capacitor WebView User-Agent patterns
- Removes X-Frame-Options only for mobile app, keeps protection for browsers

This allows the mobile app to embed the website in an iframe while
maintaining clickjacking protection for regular web browsers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tasks/middleware/__init__.py

@@ -0,0 +1,3 @@
+from .mobile_app import AllowMobileAppFramingMiddleware
+
+__all__ = ['AllowMobileAppFramingMiddleware']

tasks/middleware/mobile_app.py

@@ -0,0 +1,39 @@
+"""
+Middleware to allow iframe embedding for the KeepItGoing mobile app.
+
+The mobile app uses Capacitor WebView which embeds the website in an iframe.
+This middleware detects requests from the mobile app and removes X-Frame-Options
+header to allow iframe embedding, while keeping clickjacking protection for
+regular web browsers.
+"""
+
+
+class AllowMobileAppFramingMiddleware:
+    """
+    Remove X-Frame-Options header for requests from KeepItGoing mobile app.
+
+    The mobile app uses a Capacitor WebView with a specific User-Agent pattern.
+    We detect these requests and allow iframe embedding for them.
+    """
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        response = self.get_response(request)
+
+        # Check if request is from KeepItGoing mobile app
+        user_agent = request.META.get('HTTP_USER_AGENT', '')
+
+        # Capacitor apps include "CapacitorHttp" or the app package name in User-Agent
+        is_mobile_app = (
+            'CapacitorHttp' in user_agent or
+            'com.firebugit.keepitgoing' in user_agent or
+            'KeepItGoing' in user_agent and 'Mobile' in user_agent
+        )
+
+        # Remove X-Frame-Options for mobile app requests
+        if is_mobile_app and 'X-Frame-Options' in response:
+            del response['X-Frame-Options']
+
+        return response