fix(api_server): report hermes version on /health and /health/detailed (#40620)

Salvaged from #40479; re-verified on main, tightened, tested.

Co-authored-by: tfournet <tfournet@users.noreply.github.com>

tests/gateway/test_api_server.py

@@ -497,6 +497,20 @@ class TestHealthEndpoint:
             assert data["status"] == "ok"
             assert data["platform"] == "hermes-agent"
 
+    @pytest.mark.asyncio
+    async def test_health_reports_version(self, adapter):
+        """GET /health must expose a non-empty version so orchestrators (e.g.
+        AgentOS) can read the gateway version without scraping. Regression
+        guard for the missing-version gap."""
+        app = _create_app(adapter)
+        async with TestClient(TestServer(app)) as cli:
+            resp = await cli.get("/health")
+            assert resp.status == 200
+            data = await resp.json()
+            assert "version" in data
+            assert isinstance(data["version"], str)
+            assert data["version"] != ""
+
     @pytest.mark.asyncio
     async def test_v1_health_alias_returns_ok(self, adapter):
         """GET /v1/health should return the same response as /health."""
@@ -507,6 +521,7 @@ class TestHealthEndpoint:
             data = await resp.json()
             assert data["status"] == "ok"
             assert data["platform"] == "hermes-agent"
+            assert data.get("version")
 
 
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