fix: apply local patches for self-hosted dev environment

- Caddyfile: add security headers, X-Forwarded-For, serve app from static files
- compose: add FLUXER_API_PUBLIC_ENDPOINT for admin service
- rate limits: relax auth register/login for dev (50/60s)
- rspack: read CDN_ENDPOINT from env instead of hardcoded fluxerstatic.com
- gitignore: add dev/secret.txt
- add dev/livekit.yaml for local LiveKit config

.gitignore

@@ -34,6 +34,7 @@
 **/fluxer.env
 **/secrets.env
 /dev/fluxer.env
+/dev/secret.txt
 
 # Logs, temporary files, and binaries
 **/*.beam