Require verification evidence from implementers

[TheGreatAxios]

Summary

• Implementation workers run every defined verification command and report exact outcomes and exit statuses.
• Skywalker routes every delegated Builder implementation through Critic, with Greybeard remaining additional for architecture work.
• Shared prompt contracts and architecture documentation require unavailable checks to appear as evidence-backed Blockers.

Verification

• bun test src/agent/directors/builder/package.test.ts src/agent/directors/skywalker/package.test.ts src/agent/prompts.test.ts exits 0 with 55 passing tests
• bun run check exits 0

Part of CL-6804

[linear-code]

CL-6804

[TheGreatAxios]

Review · Comment

Automated whole-branch review found no findings. bun run check exits 0. Sawyer's prompt-diff review is required before merge.