refactor(api): consolidate health check endpoints to /health

Removes the redundant `/healthz` and `/api/v1/health` endpoints, leaving `/health` as the sole health check endpoint.

- Update router to return 404 Not Found for the removed endpoints
- Update admin log filtering to only ignore `/health`
- Remove health URL from API documentation data
- Update tests to verify `/health` returns 200 and others return 404
- Update README documentation to reflect the change

README.md

@@ -108,8 +108,7 @@ The compose example also works with Podman compatible compose tools. Its data vo
 `./data:/data:Z` for SELinux relabeling, and the container overrides runtime paths to use
 `/data`, `/app/static`, and `/app/templates`.
 
-The image exposes `/health`, `/healthz`, and `/api/v1/health`. Docker and compose healthchecks
-use `/health`.
+The image exposes the health endpoint: `/health`. Docker and compose healthchecks use it.
 
 ## Reverse Proxy Security