refactor(core): migrate DeepReview runtime ownership

[limityan]

Summary

• Move DeepReview provider-neutral queue timing, capacity decisions, retry/backoff state, result shaping, diagnostics formatting, incremental cache selection, and cache-hit/cache-miss report signal shaping into bitfun-agent-runtime.
• Simplify core TaskTool / CodeReviewTool paths so core keeps product-context side effects: launch, event emission, queue sleeping, session metadata IO, persistence, and product Tool adapters.
• Delete the old core queue timing module and duplicate core-side DeepReview cache/packet tests; runtime now owns the behavior coverage.
• Extend core-boundary rules and self-tests to prevent migrated DeepReview task-execution, report, and cache ownership from flowing back into core.
• Update the core decomposition plan/completed notes for the migrated DeepReview runtime owner scope.

Compatibility and risk

• No Cargo dependency changes.
• Existing core compatibility exports are preserved for old DeepReview policy paths.
• User-visible DeepReview behavior is intended to remain unchanged: queue status, retry guidance, capacity skip payloads, cached reviewer results, and report reliability signals keep their existing shapes.
• Core still owns concrete side effects that need product context: session metadata, persistence IO, event emission, queue sleeping, task launch, and provider invocation.

Verification

• cargo test -p bitfun-agent-runtime deep_review::report --lib
• cargo test -p bitfun-agent-runtime deep_review::task_execution --lib
• cargo test -p bitfun-core --features product-full deep_review --lib
• node --test scripts/check-core-boundaries.test.mjs
• node scripts/check-core-boundaries.mjs
• cargo check -p bitfun-core --no-default-features
• cargo check --workspace
• cargo metadata --no-deps --format-version 1
• pnpm run check:repo-hygiene
• git diff --check