refactor(core): migrate DeepReview capacity decisions to runtime

[limityan]

Summary

• move DeepReview provider capacity error, provider queue, and blocked admission queue decisions into bitfun-agent-runtime
• keep core task adapter responsible for BitFunError fact extraction, event emission, queue sleep, runtime state writes, and admission guards
• extend boundary rules and runtime contract tests so core cannot re-own these DeepReview task-execution decisions
• update core decomposition plan/completed docs to narrow remaining DeepReview work to launch/provider-wait side effects and report persistence

Risk

• No intended behavior change. Provider quota/fail-fast handling, retry-after bounds, queue cancel/pause/skip, active-reviewer early retry, and local admission queue expiry are covered by focused tests.
• DeepReview concrete launch, provider wait side effects, and report persistence remain in core and are not claimed as complete.

Validation

• cargo test -p bitfun-agent-runtime
• cargo test -p bitfun-core deep_review_ --features product-full
• node --test scripts/check-core-boundaries.test.mjs
• node scripts/check-core-boundaries.mjs
• cargo check -p bitfun-core --no-default-features
• cargo check -p bitfun-core --features product-full
• cargo metadata --no-deps --format-version 1
• cargo tree -p bitfun-agent-runtime --edges normal --depth 1
• cargo check --workspace
• pnpm run check:repo-hygiene
• git diff --check