fix(services): conditional caddy_net across all Docker service scripts

Only include the caddy_net network block in generated docker-compose.yml
files when ~/docker/caddy exists. Prevents "network caddy_net declared
as external, but could not be found" on standalone installs without Caddy.

Affected: actualbudget, archivebox, arm, audiobookshelf, calibre-web,
changedetection, drum-rhythm-game, emby, fmd, frigate, frigate-audio,
frigate-notify, gatus, homeassistant, immich, iopaint, jellyfin, joplin,
koha, lyrion, magicmirror, mail-archiver, mattermost, mealie, meshcentral,
n8n, nextcloud, ntfy, onlyoffice, portainer, stirling-pdf, syncthing,
traccar, unifi, uptimekuma, vaultwarden, wg-easy

Skipped: authelia (creates caddy_net itself), caddy, crowdsec, wolf,
wolf-pair, and services using network_mode: host with no caddy_net.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D8ckUJQtj1pH8jtAddBDZs

services/frigate-notify.sh

@@ -211,7 +211,24 @@ install_frigate-notify() {
     ensure_docker_dir_ownership "$FN_DIR"
     cd "$FN_DIR" || return 1
 
-    cat > docker-compose.yml << 'FN_COMPOSE'
+    local _CADDY_NET_BLOCK=""
+    if [ -d "$DOCKER_DIR/caddy" ]; then
+        _CADDY_NET_BLOCK="    networks:
+      - caddy_net
+"
+    fi
+
+    local _CADDY_NET_SECTION=""
+    if [ -d "$DOCKER_DIR/caddy" ]; then
+        _CADDY_NET_SECTION="
+networks:
+  caddy_net:
+    external: true
+    name: ${SITE_CADDY_NET:-caddy_net}
+"
+    fi
+
+    cat > docker-compose.yml << FN_COMPOSE
 name: frigate-notify
 
 services:
@@ -222,13 +239,7 @@ services:
     restart: unless-stopped
     volumes:
       - ./config.yml:/app/config.yml:ro
-    networks:
-      - caddy_net
-
-networks:
-  caddy_net:
-    external: true
-    name: ${CADDY_NET:-caddy_net}
+${_CADDY_NET_BLOCK}${_CADDY_NET_SECTION}
 FN_COMPOSE
 
     # Smart defaults based on what's installed