Make revoking an agent and locking a dashboard actually revoke and lock

An MCP access token is a stateless JWT good until it expires, so deleting
the client row revoked nothing already handed out — on the MCP endpoint or
on the REST API, which takes the same token directly. Both doors now look
the client up by the `client_id` the token has always carried, so tokens
already in circulation are held to it too.

A dashboard's `locked` setting stopped the client drawing a control and
nothing else; the server took a publish from a panel showing it anyway. It
now bounds the panel's write scope, resolved live where a flow drives the
flag, exactly as the client resolves it. Reads are untouched — read-only is
not blind — and so is a querying chart's request, which is how that tile
reads rather than something anyone touched.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CL9zvnnvcp1mvA8o7impxk

backend/tests/api/routes/test_panels.py

@@ -345,6 +345,88 @@ def test_a_panel_speaks_only_its_own_widgets_messages(
     )
 
 
+def _publish_settings(
+    client: TestClient, headers: dict[str, str], name: str, settings_: dict
+) -> None:
+    """Give a published dashboard these settings and publish it again."""
+    saved = client.get(f"{DASHBOARDS}/{name}?draft=true", headers=headers).json()
+    saved["settings"] = settings_
+    written = client.put(f"{DASHBOARDS}/{name}", headers=headers, json=saved)
+    assert written.status_code == 200, written.text
+    published = client.post(
+        f"{DASHBOARDS}/{name}/publish",
+        headers=headers,
+        json={"version": written.json()["version"]},
+    )
+    assert published.status_code == 200, published.text
+
+
+def test_a_locked_dashboard_entitles_a_panel_to_read_and_not_to_publish(
+    client: TestClient, superuser_token_headers: dict[str, str]
+) -> None:
+    """`locked` bounds what a screen may send, not what it may draw.
+
+    It used to bound neither: the client stopped offering the control and the
+    server took the publish from anything that asked anyway.
+
+    Unions like the allowlist itself, which is what the second dashboard here
+    is for — a message a locked dashboard shows and an unlocked one controls
+    stays writable, because the unlocked one is what entitles the panel to it.
+    """
+    _dashboard_with(client, superuser_token_headers, "panel_locked", PANEL_WIDGETS)
+    _publish_settings(
+        client, superuser_token_headers, "panel_locked", {"locked": {"value": True}}
+    )
+    _dashboard_with(
+        client,
+        superuser_token_headers,
+        "panel_open",
+        [{"id": "w_button", "type": "button", "config": {"target": "demo.button"}}],
+    )
+    _panels(
+        client,
+        superuser_token_headers,
+        {"panels": [{"id": "foyer", "dashboards": ["panel_locked", "panel_open"]}]},
+    )
+    panel_headers = _pair(client, superuser_token_headers, "foyer")
+    messages = f"{settings.API_V1_STR}/messages"
+
+    # Only the locked dashboard names it, so there is nothing left to send it.
+    assert (
+        client.post(
+            f"{messages}/demo.slider", headers=panel_headers, json={"value": 1}
+        ).status_code
+        == 403
+    )
+    # 404, not 403: past the gate, and refused by an engine that knows no such
+    # message. The unlocked dashboard binds this one too.
+    assert (
+        client.post(
+            f"{messages}/demo.button", headers=panel_headers, json={"value": 1}
+        ).status_code
+        == 404
+    )
+    # A querying chart's request survives the lock: publishing it is how that
+    # tile *reads*, and a locked dashboard whose charts cannot ask goes blank
+    # rather than read-only.
+    assert (
+        client.post(
+            f"{messages}/demo.query_request",
+            headers=panel_headers,
+            json={"value": {"range_s": 3600, "interval_s": 60}},
+        ).status_code
+        == 404
+    )
+    # And what the locked dashboard draws is still readable — read-only is not
+    # blind, and a wall panel showing stale numbers is the failure to avoid.
+    assert (
+        client.get(
+            f"{messages}/demo.temperature/history", headers=panel_headers
+        ).status_code
+        == 200
+    )
+
+
 def test_a_panel_may_read_its_dashboards_own_settings(
     client: TestClient, superuser_token_headers: dict[str, str]
 ) -> None:
@@ -854,8 +936,9 @@ def test_a_socket_pushes_only_the_frames_it_was_asked_for(tmp_path) -> None:
 
     store = ArtifactStore(tmp_path / "artifacts")
     store.volatile = VolatileStore(tmp_path / "ring", limit_bytes=1_000_000)
-    frame = store.put([b"\x89PNG..."], name="f.png", media_type="image/png",
-                      volatile=True)
+    frame = store.put(
+        [b"\x89PNG..."], name="f.png", media_type="image/png", volatile=True
+    )
     kept = store.put([b"checkpoint"], name="w.pt")
 
     asking = orjson.dumps({"type": "media", "names": ["cam.frame", "other.frame"]})