feat: instant feedback button — creates Gitea issues with auto-labels

iOS:
- Subtle floating feedback button (bottom-left, speech bubble icon)
- Quick sheet: type → send → auto-creates Gitea issue
- Shows checkmark on success, auto-dismisses
- No friction — tap, type, done

Gateway:
- POST /api/feedback endpoint
- Auto-labels: bug/feature/enhancement + ios/web + fitness/brain/reader/podcasts
- Keyword detection for label assignment
- Creates issue via Gitea API with user name and source

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gateway/auth.py

@@ -12,6 +12,7 @@ import sqlite3
 
 import bcrypt
 
+from config import SESSION_COOKIE_SECURE
 from database import get_db
 from sessions import create_session, delete_session
 
@@ -58,7 +59,10 @@ def handle_logout(handler):
     delete_session(token)
     handler.send_response(200)
     handler.send_header("Content-Type", "application/json")
-    handler.send_header("Set-Cookie", "platform_session=; Path=/; HttpOnly; Secure; SameSite=Lax; Max-Age=0")
+    cookie = "platform_session=; Path=/; HttpOnly; SameSite=Lax; Max-Age=0"
+    if SESSION_COOKIE_SECURE:
+        cookie += "; Secure"
+    handler.send_header("Set-Cookie", cookie)
     resp = b'{"success": true}'
     handler.send_header("Content-Length", len(resp))
     handler.end_headers()