fix: normalise GATEWAY_HEALTH_URL to base URL before probing

The probe was appending '/detailed' to whatever URL was provided,
so GATEWAY_HEALTH_URL=http://host:8642 would try /8642/detailed
and /8642 — neither of which are valid routes.

Now strips any trailing /health or /health/detailed from the env var
and always probes {base}/health/detailed then {base}/health.
Accepts bare base URL, /health, or /health/detailed forms.

hermes_cli/web_server.py

@@ -330,13 +330,25 @@ def _probe_gateway_health() -> tuple[bool, dict | None]:
     Uses ``/health/detailed`` first (returns full state), falling back to
     the simpler ``/health`` endpoint.  Returns ``(is_alive, body_dict)``.
 
+    Accepts any of these as ``GATEWAY_HEALTH_URL``:
+    - ``http://gateway:8642``                (base URL — recommended)
+    - ``http://gateway:8642/health``         (explicit health path)
+    - ``http://gateway:8642/health/detailed`` (explicit detailed path)
+
     This is a **blocking** call — run via ``run_in_executor`` from async code.
     """
     if not _GATEWAY_HEALTH_URL:
         return False, None
 
+    # Normalise to base URL so we always probe the right paths regardless of
+    # whether the user included /health or /health/detailed in the env var.
     base = _GATEWAY_HEALTH_URL.rstrip("/")
-    for path in (f"{base}/detailed", base):
+    if base.endswith("/health/detailed"):
+        base = base[: -len("/health/detailed")]
+    elif base.endswith("/health"):
+        base = base[: -len("/health")]
+
+    for path in (f"{base}/health/detailed", f"{base}/health"):
         try:
             req = urllib.request.Request(path, method="GET")
             with urllib.request.urlopen(req, timeout=_GATEWAY_HEALTH_TIMEOUT) as resp: