feat: support shared-workspace file flow for matrix

docker-compose.yml

@@ -1,5 +1,39 @@
 services:
+  platform-agent:
+    build:
+      context: ./external/platform-agent
+      target: development
+      additional_contexts:
+        agent_api: ./external/platform-agent_api
+    env_file: .env
+    environment:
+      PYTHONUNBUFFERED: "1"
+    volumes:
+      - ./external/platform-agent/src:/app/src
+      - ./external/platform-agent_api:/agent_api
+      - workspace:/workspace
+    command: >
+      sh -lc "
+        mkdir -p /workspace &&
+        chown -R agent:agent /workspace &&
+        exec /app/.venv/bin/uvicorn src.main:app --host 0.0.0.0 --port 8000
+      "
+    ports:
+      - "8000:8000"
+    restart: unless-stopped
+
   matrix-bot:
     build: .
     env_file: .env
+    environment:
+      AGENT_BASE_URL: http://platform-agent:8000
+      AGENT_WS_URL: ws://platform-agent:8000/v1/agent_ws/
+      SURFACES_WORKSPACE_DIR: /workspace
+    depends_on:
+      - platform-agent
+    volumes:
+      - workspace:/workspace
     restart: unless-stopped
+
+volumes:
+  workspace: