docs: translate package.json description and .env.example to English

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -1,20 +1,20 @@
-# Oikos - Umgebungsvariablen
-# Kopiere diese Datei nach .env und passe die Werte an.
+# Oikos - Environment Variables
+# Copy this file to .env and adjust the values.
 
 # Server
 PORT=3000
 NODE_ENV=production
 
 # Session
-SESSION_SECRET=HIER_EINEN_LANGEN_ZUFAELLIGEN_STRING_EINTRAGEN
-# SESSION_SECURE=false   # Nur setzen wenn kein HTTPS/Reverse Proxy (z.B. direktes localhost)
+SESSION_SECRET=REPLACE_WITH_A_LONG_RANDOM_STRING
+# SESSION_SECURE=false   # Only set when not using HTTPS/reverse proxy (e.g. direct localhost)
 
-# Datenbank (SQLite/SQLCipher)
+# Database (SQLite/SQLCipher)
 DB_PATH=/data/oikos.db
-DB_ENCRYPTION_KEY=HIER_EINEN_STARKEN_VERSCHLUESSELUNGSSCHLUESSEL_EINTRAGEN
+DB_ENCRYPTION_KEY=REPLACE_WITH_A_STRONG_ENCRYPTION_KEY
 
-# Wetter (OpenWeatherMap)
-OPENWEATHER_API_KEY=DEIN_API_KEY
+# Weather (OpenWeatherMap)
+OPENWEATHER_API_KEY=YOUR_API_KEY
 OPENWEATHER_CITY=Berlin
 OPENWEATHER_UNITS=metric
 OPENWEATHER_LANG=de
@@ -22,17 +22,17 @@ OPENWEATHER_LANG=de
 # Google Calendar (optional)
 GOOGLE_CLIENT_ID=
 GOOGLE_CLIENT_SECRET=
-GOOGLE_REDIRECT_URI=https://deine-domain.de/api/v1/calendar/google/callback
+GOOGLE_REDIRECT_URI=https://your-domain.com/api/v1/calendar/google/callback
 
 # Apple Calendar CalDAV (optional)
 APPLE_CALDAV_URL=https://caldav.icloud.com
 APPLE_USERNAME=
 APPLE_APP_SPECIFIC_PASSWORD=
 
-# Kalender-Sync-Intervall in Minuten (Standard: 15)
+# Calendar sync interval in minutes (default: 15)
 SYNC_INTERVAL_MINUTES=15
 
-# Sicherheit
+# Security
 RATE_LIMIT_WINDOW_MS=60000
 RATE_LIMIT_MAX_ATTEMPTS=5
 RATE_LIMIT_BLOCK_DURATION_MS=900000