fix(agent-task): preserve Cook child retry lifecycle

[chubes4]

Summary

• retain Cook retry ownership when a detached child is cancelled
• route agent-task retry <child> --run through the owning Cook lifecycle instead of standalone execution or Lab run-plan handoff
• cover cancelled-child retry admission and controller-owned routing

Closes #11931.

Verification

• cargo fmt --all --check
• cargo check -p homeboy-agents -p homeboy-cli
• cargo test -p homeboy-agents cancelled_provider_child_retry_stays_attached_to_its_cook
• cargo test -p homeboy-agents retryable_pre_provider_retry_stays_attached_to_its_cook
• cargo test -p homeboy-agents approved_empty_provider_failure_retry_stays_attached_and_becomes_continuation_candidate
• cargo test -p homeboy-cli lab_run_retry_leaves_a_cook_child_for_controller_lifecycle

Clippy was attempted with cargo clippy -p homeboy-agents -p homeboy-cli --tests -- -D warnings; it is blocked by three pre-existing warnings in homeboy-core under the installed Clippy version.

AI assistance

OpenAI gpt-5.6-sol via OpenCode traced the retry lineage regression, implemented the lifecycle routing fix, and added regression tests. Chris Huber remains responsible for every line.

[homeboy-ci]

Homeboy Results — homeboy

Lint

✅ review lint — passed

ℹ️ Full options: homeboy self docs commands/lint
ℹ️ Save lint baseline: homeboy review lint homeboy --baseline
Deep dive: homeboy review lint homeboy --changed-since 8457533

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-homeboy-review-lint-homeboy-fast-Linux contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-homeboy-review-lint-homeboy-fast-Linux contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/homeboy/actions/runs/31246859272

Audit

⚠️ review audit — no measurement

Deep dive: homeboy review audit homeboy --changed-since 8457533

Artifacts and drill-down

• CI results artifact: homeboy-ci-results-homeboy-review-audit-homeboy-fast-Linux contains immediate command JSON for this action invocation.
• Observation artifact: homeboy-observations-homeboy-review-audit-homeboy-fast-Linux contains exported Homeboy run history for deeper queries.
• Drill-down: download the observation artifact, then run homeboy runs import <dir>, homeboy runs list, and homeboy runs findings <run-id>.
• Artifacts are attached to the workflow run: https://github.com/Extra-Chill/homeboy/actions/runs/31246859272

Tooling versions

• Homeboy CLI: homeboy 0.334.0+3de23e5aa814-dirty
• Extension: rust from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: 14fe68af
• Action: unknown@unknown