Initial commit: Matrix deployment (Synapse, Element, Caddy, Postgres)

Docker-Compose-Setup mit Synapse, Element Web, Synapse-Admin,
Caddy als Reverse Proxy und Postgres. Secrets und Laufzeitdaten
sind via .gitignore ausgeschlossen; Beispiel-Configs mit
Platzhaltern liegen als *.example bei.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y31cBx4B4b56LmzTA9wx76

.gitignore

@@ -0,0 +1,54 @@
+# ---------------------------------------------------------------
+# Secrets / Credentials  -- NIEMALS committen
+# ---------------------------------------------------------------
+secrets/*
+!secrets/*.example
+*.key
+*.pem
+*.crt
+*.p12
+*.signing.key
+synapse/homeserver.yaml
+synapse/*.signing.key
+.env
+.env.*
+!.env.example
+
+# ---------------------------------------------------------------
+# Laufzeit-Daten der Container (Volumes / Bind Mounts)
+# ---------------------------------------------------------------
+postgres/
+synapse/media_store/
+synapse/homeserver.pid
+caddy/data/
+caddy/config/
+
+# ---------------------------------------------------------------
+# Logs
+# ---------------------------------------------------------------
+*.log
+logs/
+
+# ---------------------------------------------------------------
+# Backups / Dumps / Archive
+# ---------------------------------------------------------------
+*.sql
+*.dump
+*.bak
+*.tar
+*.tar.gz
+*.zip
+backup/
+backups/
+
+# ---------------------------------------------------------------
+# OS / Editor
+# ---------------------------------------------------------------
+Thumbs.db
+ehthumbs.db
+desktop.ini
+.DS_Store
+*.swp
+*~
+.idea/
+.vscode/