[test-recorder] Interface-parity contract in AGENTS.md is unenforced; guide copy already drifts from the record flow

### Problem
`tools/test-recorder/AGENTS.md:30-43` declares an interface-parity contract across three audiences (human TTY, agent non-TTY, agent-supervising-human via `guide`), but nothing enforces it:

- No contract test connects each interactive prompt to its flag/command equivalent; adding a prompt to `record.ts` compiles and passes tests without adding a flag or `guide` update (`src/commands/recordPrefill.test.ts`, `src/cli/flags.test.ts`).
- `src/commands/guide.ts:18-33,58-74` is a manually duplicated snapshot of the record flow — it already drifts (guide says the tool "opens the PR"; the flow only offers it after optional cleanup). No tests cover guide.ts.
- `src/useCases.ts:1-42` IDs are manually repeated in CLI help (`src/index.ts:206-208`) and guide copy (`src/commands/guide.ts:25`).

### Suggested fix
Define setup capabilities declaratively (field ID, parser, validator, interactive collector, flag exposure, guide copy) in one registry; generate command schemas/help from it; add a contract test asserting every field has both interactive and automation adapters and that guide copy references every required flag.

_Line references are against branch `cb/comfy-test-usability` (PR #15837); adjust after merge._