feat(FN-010): implement code-server spawn service with Docker Compose

- Add SpawnService with container lifecycle (spawn/stop/status)
- Generate Docker Compose services from tool manifests
- Integrate Traefik label generation with subdomain routing
- Mount workspace, config, and SSH key volumes
- Add container status polling and health checks
- Enhance tool instance API with spawn/stop/start/status endpoints
- Add Traefik forwardAuth middleware for auth proxy
- Update code-server manifest with runtime configuration

apps/api/app/models/tool_instance.py

@@ -34,6 +34,9 @@ class ToolInstance(Base, UUIDMixin, TimestampMixin):
     config_override: Mapped[dict[str, Any] | None] = mapped_column(
         JSON, nullable=True
     )
+    traefik_labels: Mapped[dict[str, Any] | None] = mapped_column(
+        JSON, nullable=True
+    )
 
     project: Mapped["Project"] = relationship(
         back_populates="tool_instances"