fix(dashboard): allow chat websockets on insecure public bind

Allow non-loopback websocket peers when the dashboard is explicitly exposed with --host 0.0.0.0/:: and --insecure.

This fixes the failure mode where /chat rendered over LAN but /api/ws and /api/events were rejected with HTTP 403, leaving the embedded TUI chat disconnected.

Add regression coverage for the insecure public bind case in the dashboard websocket auth tests.

tests/hermes_cli/test_dashboard_auth_ws_auth.py

@@ -80,6 +80,25 @@ def loopback_app():
     web_server.app.state.auth_required = prev_required
 
 
+@pytest.fixture
+def insecure_public_app():
+    """web_server.app configured for all-interfaces insecure mode."""
+    _reset_for_tests()
+    clear_providers()
+    prev_host = getattr(web_server.app.state, "bound_host", None)
+    prev_port = getattr(web_server.app.state, "bound_port", None)
+    prev_required = getattr(web_server.app.state, "auth_required", None)
+    web_server.app.state.bound_host = "0.0.0.0"
+    web_server.app.state.bound_port = 9120
+    web_server.app.state.auth_required = False
+    client = TestClient(web_server.app, base_url="http://192.168.0.222:9120")
+    yield client
+    _reset_for_tests()
+    web_server.app.state.bound_host = prev_host
+    web_server.app.state.bound_port = prev_port
+    web_server.app.state.auth_required = prev_required
+
+
 def _logged_in(client: TestClient) -> None:
     """Drive the stub OAuth round trip so the client holds session cookies."""
     r1 = client.get("/auth/login?provider=stub", follow_redirects=False)
@@ -281,6 +300,21 @@ class TestWsRequestIsAllowedGated:
         ws.headers = {"host": "127.0.0.1:8080"}
         assert web_server._ws_request_is_allowed(ws) is True
 
+    def test_non_loopback_peer_allowed_in_insecure_public_mode(self, insecure_public_app):
+        """`--host 0.0.0.0 --insecure` is an explicit LAN/public opt-in.
+
+        Regression coverage for the dashboard `/chat` breakage where the
+        HTML shell loaded on 9120 but every WebSocket upgrade was rejected
+        with 403 because the loopback-only peer guard still ran even though
+        the operator intentionally exposed the dashboard on all interfaces.
+        """
+        ws = _fake_ws(query={}, client_host="192.168.0.55")
+        ws.headers = {
+            "host": "192.168.0.222:9120",
+            "origin": "http://192.168.0.222:9120",
+        }
+        assert web_server._ws_request_is_allowed(ws) is True
+
     def test_host_origin_guard_still_runs_in_gated_mode(self, gated_app):
         """Bypassing the peer-IP check must not bypass the DNS-rebinding
         Host header guard — that one still protects against attacker