fix: Change UI language to English and fix notification toggle bug

Changes:
- Convert all Polish UI text to English (buttons, labels, messages)
  - Menu: "Powiadomienia" → "Notifications"
  - Status badges: "Włączone/Wyłączone/Zablokowane" → "Enabled/Disabled/Blocked"
  - Toast messages: all notification messages translated to English
  - Notification bodies: "Nowe: X kanały" → "New: X channels"

- Fix notification toggle UI bug
  - Badge now correctly shows "Disabled" when user turns off notifications
  - Previously showed "Enabled" whenever permission was granted (ignoring localStorage)
  - Now checks both permission AND localStorage state

This ensures the UI respects the international nature of the project
and fixes the toggle state display issue found during Android testing.

Files modified:
- app/templates/base.html
- app/static/js/app.js
- app/static/js/dm.js

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

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

app/templates/base.html

@@ -68,11 +68,11 @@
                     <i class="bi bi-bell" style="font-size: 1.5rem;"></i>
                     <div class="flex-grow-1">
                         <div class="d-flex justify-content-between align-items-center">
-                            <span>Powiadomienia</span>
-                            <span id="notificationStatus" class="badge bg-secondary">Wyłączone</span>
+                            <span>Notifications</span>
+                            <span id="notificationStatus" class="badge bg-secondary">Disabled</span>
                         </div>
                         <small class="text-muted d-block mt-1" style="font-size: 0.75rem;">
-                            Działa gdy app w tle
+                            Works when app is hidden
                         </small>
                     </div>
                 </button>