Adds a new FeatureType.AiCreditSystem that enables model-based token
pricing with per-model markup configuration. Includes the @useautumn/ai-sdk
package for Vercel AI SDK integration with automatic token tracking.
Co-authored-by: TheUntraceable <73362400+TheUntraceable@users.noreply.github.com>
When check is called with lock=true on an unlimited-balance feature,
the deduction executors skipped the entire iteration (including lock
receipt save), causing finalize to fail with "Lock not found". Now
saves an empty lock receipt before continuing so finalize can find,
claim, and delete it as a no-op.
Co-authored-by: Cursor <cursoragent@cursor.com>
