feat(grok): guard interactive roles from GROK routes (interim)

intake (prompter) and secretary run a held-open chat session driven by the
Claude Agent SDK. GROK has no interactive runtime yet, and a GROK route for
those slugs would be spawned with the route creds injected as ANTHROPIC_*
against api.x.ai/v1 — the wrong protocol — producing a silent, empty reply
(the blank intake we observed).

Downgrade a GROK route for intake-1/secretary-1 to the Anthropic default with
a logged warning. The one-shot delivery roles route to GROK unchanged. This
guard is replaced by the real interactive fork once the opencode interactive
driver lands.

tests/unit/services/test_llm_routing_interactive_guard.py

@@ -0,0 +1,60 @@
+"""The interactive-role routing guard keeps intake/secretary off GROK.
+
+GROK has no interactive runtime yet, and the interactive spawn would inject the
+route's creds as ANTHROPIC_* against api.x.ai/v1 (wrong protocol → silent empty
+reply). Until the opencode interactive driver lands, a GROK route for those
+slugs is downgraded to the Anthropic default. The one-shot delivery roles route
+to GROK unchanged. DB-free: exercises `_guard_interactive` directly.
+"""
+
+from __future__ import annotations
+
+import structlog
+from roboco.models.base import ModelProvider
+from roboco.services.llm import AgentRoute, ModelRoutingService
+
+
+def _svc() -> ModelRoutingService:
+    svc = ModelRoutingService.__new__(ModelRoutingService)
+    svc.log = structlog.get_logger()
+    return svc
+
+
+def _grok_route() -> AgentRoute:
+    return AgentRoute(
+        provider_id=None,
+        provider_type=ModelProvider.GROK,
+        base_url="https://api.x.ai/v1",
+        auth_token="xai-key",
+        model_name="grok-build-0.1",
+    )
+
+
+def test_grok_interactive_role_downgrades_to_anthropic() -> None:
+    svc = _svc()
+    for slug in ("intake-1", "secretary-1"):
+        route = svc._guard_interactive(_grok_route(), slug, "prompter")
+        assert route.provider_type == ModelProvider.ANTHROPIC
+        # No xAI creds leak onto the Claude SDK path.
+        assert route.base_url is None
+        assert route.auth_token is None
+
+
+def test_grok_delivery_role_is_left_on_grok() -> None:
+    svc = _svc()
+    route = svc._guard_interactive(_grok_route(), "be-dev-1", "developer")
+    assert route.provider_type == ModelProvider.GROK
+    assert route.base_url == "https://api.x.ai/v1"
+
+
+def test_non_grok_interactive_route_is_unchanged() -> None:
+    svc = _svc()
+    anthropic = AgentRoute(
+        provider_id=None,
+        provider_type=ModelProvider.ANTHROPIC,
+        base_url=None,
+        auth_token=None,
+        model_name="claude-opus-4-6",
+    )
+    route = svc._guard_interactive(anthropic, "intake-1", "prompter")
+    assert route is anthropic