Reverse proxies (Traefik, Caddy, nginx) often normalize or reject URLs
containing %2F (encoded slash). Alert IDs contain forward slashes
(e.g., "docker-container-state-docker:abc/def"), causing acknowledge
requests to fail with 400 errors when going through a reverse proxy.
Added new body-based endpoints that accept alert ID in JSON body:
- POST /api/alerts/acknowledge {"id": "..."}
- POST /api/alerts/unacknowledge {"id": "..."}
- POST /api/alerts/clear {"id": "..."}
Updated frontend to use the new endpoints. Legacy path-based endpoints
are preserved for backwards compatibility.
Related to #1026
rcourtman
fa43628cde