feat: implement skeleton phase

src/beaver_gateway/agents/raycast.py

@@ -0,0 +1,15 @@
+"""Raycast agent definition."""
+
+from __future__ import annotations
+
+from raycast_api import Source
+
+from beaver_gateway.agents.base import BaseAgent
+
+
+class RaycastAgent(BaseAgent):
+    """Agent backed by ``raycast-api``."""
+
+    streaming: bool = True
+    available_native_tools: tuple[str, ...] = ()
+    source: Source = Source.AI_CHAT