feat: implement skeleton phase

examples/config.py

@@ -0,0 +1,18 @@
+# Stub user config for the Phase 0 DoD.
+#
+# Loader (beaver_gateway/config_loader.py) execs this file with
+# ClaudeAgent, RaycastAgent, McpServer, ExposedMcp, Gateway already
+# bound. The top-level `gateway = Gateway(...)` is what gets picked up.
+
+gateway = Gateway(  # type: ignore[name-defined]  # noqa: F821
+    agents=[
+        ClaudeAgent(  # type: ignore[name-defined]  # noqa: F821
+            name="stub",
+            model="claude-sonnet-4-5",
+            system_prompt="You are a stub agent used to validate the Phase 0 skeleton.",
+            cwd="/tmp",
+        ),
+    ],
+    mcps=[],
+    frontends=[],
+)

examples/docker-compose.yml

@@ -0,0 +1,20 @@
+# Minimal compose for the Phase 0 DoD: build the image, mount a
+# single-file user config, watch the process print its summary line
+# and exit cleanly.
+#
+# Real deployments add a postgres service, raycast-config.json bind,
+# ~/.config/claude bind, etc. — Phase 5 lives in a separate example
+# repo (see PLAN §5.1).
+
+services:
+  gateway:
+    build:
+      context: ..
+      dockerfile: Dockerfile
+    environment:
+      DATABASE_URL: "sqlite:///./gateway.db"
+      ADMIN_USER: "admin"
+      ADMIN_PASS: "change-me"
+      SESSION_SECRET: "dev-secret-change-me"
+    volumes:
+      - ./config.py:/config/config.py:ro