Perf: 9 Performance-Fixes — SW by-v1072

Backend:
- DB: 3 neue Indizes (forum_posts thread+user, routes user) — Forum/Routen-Queries
- Caching: cache.py (TTL-Cache ohne neue Dependency) für 5 statische Listen
  (training_exercises, pflege_tipps, wiki_stats, wiki_gruppen, help_articles)
- diary.py + breeder_photos.py: Bildverarbeitung (ffmpeg/PIL/EXIF) per
  run_in_executor → blockiert Event-Loop nicht mehr
- scheduler.py: 11 kollidierende Jobs auf 5-Min-Intervalle gestaggert, coalesce=True
- social.py: ORDER BY RANDOM() ohne LIMIT in 2 Stellen gefixt
- alerts.py: Haversine-Loop bekommt SQL-Bounding-Box-Vorfilter

Frontend:
- sw.js: Tile-Cache mit LRU-Eviction (max 500 Einträge)
- admin.js: Event-Listener-Leak — Tab-Klicks per Delegation statt N Listener
- api.js: compressImage() Helper — Client-seitiges Resize auf max 2000px
  (HEIC/Videos/<500KB unverändert), integriert in 8 Upload-Stellen
  (diary, dog-profile×2, walks, poison, lost, health×2)

Bump APP_VER 1071 → 1072 (sw.js, app.js, main.py, index.html)

backend/static/js/pages/dog-profile.js

@@ -762,8 +762,10 @@ window.Page_dog_profile = (() => {
       const file = e.target.files[0];
       if (!file) return;
       try {
+        // Client-Side-Kompression vor Upload (HEIC bleibt unverändert)
+        const toUpload = await API.compressImage(file);
         const fd = new FormData();
-        fd.append('file', file);
+        fd.append('file', toUpload);
         const result = await API.dogs.uploadPhoto(dog.id, fd);
         // Position zurücksetzen
         await API.dogs.updatePhotoPosition(dog.id, 1.0, 0.0, 0.0);
@@ -1384,8 +1386,10 @@ window.Page_dog_profile = (() => {
         // Foto hochladen wenn gewählt
         if (fotoFile) {
           try {
+            // Client-Side-Kompression vor Upload
+            const toUpload = await API.compressImage(fotoFile);
             const fd = new FormData();
-            fd.append('file', fotoFile);
+            fd.append('file', toUpload);
             const result = await API.dogs.uploadPhoto(saved.id, fd);
             saved.foto_url = result.foto_url;
             _appState.activeDog = { ...saved };