feat: security hardening and HTTPS/SSO infrastructure configs

- Narrow trusted proxies, remove overly broad 10.0.0.0/8
- Fail closed on missing SSH known_hosts in terminal proxy
- Add Navidrome reverse proxy headers for Authelia SSO
- Add Gitea docker-compose definition
- Add Caddy configs for NAS and VPS edge proxies
- Add dnsmasq split-horizon DNS config
- Add security execution plan document

tmp_remote/Caddyfile_vps

@@ -0,0 +1,54 @@
+(security_headers) {
+	header {
+		X-Content-Type-Options nosniff
+		X-Frame-Options SAMEORIGIN
+		Referrer-Policy strict-origin-when-cross-origin
+		X-XSS-Protection "1; mode=block"
+		-Server
+	}
+}
+
+(authelia) {
+	forward_auth 100.78.131.124:9092 {
+		uri /api/verify?rd=https://auth.jimmygan.com
+		copy_headers Remote-User Remote-Groups Remote-Name Remote-Email
+	}
+}
+
+# Authelia portal (no forward_auth on itself)
+auth.jimmygan.com {
+	import security_headers
+	reverse_proxy 100.78.131.124:9092
+}
+
+# Protected services
+nas.jimmygan.com {
+	import security_headers
+	import authelia
+	reverse_proxy 100.78.131.124:4000
+}
+
+music.jimmygan.com {
+	import security_headers
+	import authelia
+	reverse_proxy 100.78.131.124:4533 {
+		flush_interval -1
+	}
+}
+
+photos.jimmygan.com {
+	import security_headers
+	import authelia
+	reverse_proxy 100.78.131.124:2283 {
+		header_up X-Forwarded-Proto https
+		header_up X-Forwarded-Host {host}
+	}
+}
+
+photos-app.jimmygan.com {
+	import security_headers
+	reverse_proxy 100.78.131.124:2283 {
+		header_up X-Forwarded-Proto https
+		header_up X-Forwarded-Host {host}
+	}
+}