fix: complete Project Toolchain migrate Human Mode

[codeacme17]

Summary

• add a styled default-safe TTY migration preview and in-process confirmation flow
• keep lifecycle resume tokens internal while supporting full exact diff review
• cover confirmation, decline, cancellation, registry permission, stale preview, rollback, and completion
• render complete non-TTY Agent JSON commands without inactive choices or placeholders
• preserve the existing typed JSON lifecycle protocol and migration invariants

Validation

• node --test test/toolchain-lifecycle.test.js test/prompt-adapters.test.js — 95 passed, 3 documented adjacent TODOs
• npm run validate:acceptance — 25 P0 requirements, 39 P1 requirements, and 17 release gates passed
• packed-artifact validation — passed
• git diff --check origin/dev...HEAD — passed
• Standards review — passed
• Spec review — passed

Addresses #204.

The adjacent restore and clean Human presentation gaps are recorded as explicit TODO regressions without expanding this migration fix.