fix(resnapshot): update task objective

[lafawnduh1966]

Summary

Fixes the release-review blocker found on #147: quay task resnapshot updated the task snapshot but left the task objective artifact stale, so the next worker/reviewer prompt could still enforce the old ticket objective.

Changes

• Write a fresh task-level task_objective artifact when resnapshot changes the ticket snapshot.
• Prefer the latest task-level task_objective/ticket_snapshot artifact in worker, reviewer, goal, admin, retarget, and umbrella-final-PR paths.
• Update goal task objective text on resnapshot when a goal row exists.
• Hash the exact stored post-resnapshot snapshot content in the audit event.
• Cover next-review prompt behavior and latest-objective selection in tests.

Validation

• bun install --frozen-lockfile
• bun test packages/cli/tests/resnapshot/task_resnapshot.test.ts packages/cli/tests/core/worker_prompt.test.ts packages/cli/tests/adapters/test_github_adapter_merge_method.test.ts
• bun run typecheck
• bun run build
• env QUAY_DATA_DIR=/private/tmp/quay-release-147-fix-testdata QUAY_CONFIG_DIR=/private/tmp/quay-release-147-fix-testconfig bun test

Full suite result: 1334 pass, 5 skip, 0 fail.