[ci skip] fix widget issues: ports, Immich v2 API, Nextcloud trusted domains

- qBittorrent: use service port 80 (not container port 8080)
- Immich: add version=2 for new API endpoints (/api/server/*)
- Nextcloud: use external URL (internal rejects untrusted Host header)
- HA London: remove widget (token expired, needs manual regeneration)
- Headscale: remove widget (requires nodeId param, not overview)

stacks/platform/modules/reverse_proxy/main.tf

@@ -290,9 +290,6 @@ module "ha-london" {
     "gethomepage.dev/icon"         = "home-assistant.png"
     "gethomepage.dev/group"        = "Smart Home"
     "gethomepage.dev/pod-selector" = ""
-    "gethomepage.dev/widget.type"  = "homeassistant"
-    "gethomepage.dev/widget.url"   = "http://ha-london.viktorbarzin.lan:8123"
-    "gethomepage.dev/widget.key"   = var.haos_homepage_token
   }
 }