feat: add Goldfish Recap YouTube summary PWA

YouTube subtitles via OpenRouter become persistent, shareable recaps
with timestamp jump links, PIN-protected creation, and Traefik deploy.

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -0,0 +1,13 @@
+# PIN für Recap-Erstellung (4–6 Ziffern empfohlen)
+APP_PIN=1234
+
+# JWT — zufälligen langen String generieren (openssl rand -hex 32)
+JWT_SECRET=change-me-to-a-long-random-string
+JWT_EXPIRE_DAYS=90
+
+# OpenRouter
+OPENROUTER_API_KEY=
+OPENROUTER_MODEL=google/gemini-2.5-flash
+
+# Optional lokal
+# APP_URL=http://localhost:8000