feat: add --json, --non-interactive flags and exit-code taxonomy

Make the CLI usable by AI agents and CI bots:

- Global `--json` flag emits a single JSON object/array on stdout and a
  structured `{ error: { code, message, hint, traceId } }` envelope on
  stderr. Suppresses spinners, progress bars, and ANSI color so output
  pipes cleanly into `jq`. Wired into `publish` (final result with
  revisionId, URL, status, timelines) and `create` (including
  `--dry-run`, which now emits the resolved build config as JSON).

- Global `-y, --non-interactive, --yes` flag makes `requireInteractive()`
  fail fast with a clear `NON_INTERACTIVE_REQUIRED` error instead of
  hanging on stdin, even on a TTY. Same flag on both `deploy` and
  `sandbox` roots.

- `ExitCode` enum (OK=0, GENERIC=1, USAGE=2, AUTH=3, NOT_FOUND=4,
  CONFLICT=5, NETWORK=6). `error()` accepts `{ code, errorCode, hint,
  response }` and exits with the matching numeric code. tRPC errors are
  mapped via `mapTrpcError()`: 401/403/NOT_AUTHENTICATED/TOKEN_EXPIRED →
  AUTH, 404 → NOT_FOUND, 409 → CONFLICT, 5xx → NETWORK. Invalid-token
  path emits `AUTH_INVALID_TOKEN` with an explicit hint pointing at
  `DENO_DEPLOY_TOKEN` rather than retrying through a browser.

- Move the keychain-unavailable warning from stdout to stderr so it
  doesn't pollute machine-readable output.

Adds `tests/agent.test.ts` covering JSON dry-run, non-interactive
short-circuit, `AUTH_INVALID_TOKEN` envelope, and the `-y` alias.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 2 people