Framework-agnostic server-side tool implementations.
These tools (memory, session inspector, skill runtime, compact, overlay) and
the [ToolSurfaceFactory] depend only on lower crates (bamboo-agent-core,
bamboo-engine, bamboo-infrastructure, bamboo-memory, bamboo-tools) —
never on bamboo-server's AppState. Server-bound tools (sub-agent,
schedule) live in bamboo-server::tools and reach this crate through ports.