feat: implement tool workshop - comprehensive tool system enhancement

- Add Docker Compose and Dockerfile support for tool definitions
- Implement readiness probes with configurable command, timeout, interval
- Create ConfigFolder model for reusable file collections with project overrides
- Add rich tool config fields: port_override, start_command, working_directory, env vars, volumes
- Build unified Tool Workshop UI at /tool-workshop replacing /tool-configs and /tool-types
- Update instance creation to support dockerfile builds, config folder mounting, readiness probes
- Add 3 database migrations for tool_types, tool_configs, and new config_folders table
- Create docker_build.py and readiness_probe.py services
- Add config_folders API with CRUD and project override endpoints

Quality gates: frontend build passes, Python syntax valid, all phases complete

Addresses tool-workshop OpenSpec change

apps/api/src/models/tool_config.py

@@ -33,6 +33,15 @@ class ToolConfig(UUIDPrimaryKeyMixin, TimestampMixin, Base):
     file_path: Mapped[str | None] = mapped_column(
         String(1024), nullable=True
     )  # Only for file type
+    port_override: Mapped[int | None] = mapped_column(nullable=True)
+    start_command: Mapped[str | None] = mapped_column(Text, nullable=True)
+    working_directory: Mapped[str | None] = mapped_column(Text, nullable=True)
+    environment_variables: Mapped[dict | None] = mapped_column(
+        JSON, default=dict, nullable=True
+    )
+    volumes: Mapped[list[dict] | None] = mapped_column(
+        JSON, default=list, nullable=True
+    )
 
     user: Mapped["User"] = relationship()
     tool_type: Mapped["ToolType"] = relationship()