Summary

• Move turn outcome lifecycle planning into bitfun-agent-runtime; the core scheduler now executes the returned plan instead of owning the branching policy.
• Move SessionControl input validation, defaults, tool-use rendering, result text, and cancel-route decisions into bitfun-agent-runtime; core keeps workspace resolution, session manager calls, scheduler/coordinator cancellation, and ToolResult wrapping.
• Update the M3 plan/completed docs and the agent-runtime module guide to reflect the migrated owner boundary.

Risk / compatibility

• No intended changes to tool schema, permissions, /goal, continuation wire shape, session execution, or queue semantics.
• No Cargo dependency changes; bitfun-agent-runtime still does not depend on bitfun-core or platform/concrete service crates.
• Concrete session lifecycle, metadata/persistence IO, event emitter wiring, permission UI/channel waits, concrete prompt assembly, and product tool execution remain in core/Product Assembly adapters.

Verification

• cargo test -p bitfun-agent-runtime
• cargo test -p bitfun-core session_control --features product-full -- --nocapture
• cargo test -p bitfun-core scheduler --features product-full -- --nocapture
• cargo check -p bitfun-core --features product-full
• cargo check --workspace
• node scripts/check-core-boundaries.mjs
• pnpm run check:repo-hygiene