Separate adopter Standards state and adoption history

[KimGLee]

Fixes #123.

This change separates three responsibilities that had accumulated in K00/03:

• Kernel Markdown owns governance rules only.
• .cambium/governance/standards_state.yaml owns one adopter's current Standards/Profile identity.
• .cambium/receipts/standards-adoptions.jsonl owns append-only adoption history.

It adds a one-time compatibility migration for existing runtimes, advances active-task adoption as a guarded four-state transaction, preserves governance-only state before task-runtime initialization, and updates consumers, schemas, Cards, Read Sets, tests, and generated interfaces to the new authority boundary.

Validation performed locally:

• make check
• 161 check_queue tests
• 169 adopt_standards tests
• 102 required-queue, proof, and onboarding tests
• targeted Standards-state, migration, Profile-adoption, Profile-admission, initialization, vocabulary, and runtime-safety tests
• Python compile and git diff checks