fix: respect AbortSignal in run() — throw on pre-aborted and mid-polling abort

[MaxwellCalkin]

Fixes #370.

Summary

replicate.run() ignores AbortSignal in three ways:

1. Pre-aborted signal ignored: If signal.aborted is already true before calling run(), the SDK starts the prediction anyway instead of throwing immediately.
2. Signal not forwarded to HTTP requests: The signal was destructured from options but never passed to predictions.create() or predictions.get() during polling, so aborting could not cancel in-flight HTTP requests or interrupt sleep timers.
3. No error thrown on abort: After canceling the prediction, run() returned undefined silently instead of throwing an AbortError, making it impossible for callers to distinguish an abort from a failure or empty output.

Changes

• Check signal.aborted before starting the prediction and throw AbortError immediately
• Pass signal through to predictions.create() so the initial HTTP request respects the signal
• Pass signal to wait() and forward it to all predictions.get() polling calls
• Make sleep() in wait() abort-aware: listen for the abort event to resolve immediately instead of waiting the full polling interval
• Throw AbortError (with error.name = "AbortError") after canceling the prediction, matching standard AbortSignal behavior (e.g., how fetch handles abort)
• Update TypeScript type definitions to include signal option on wait()
• Update existing abort test to expect thrown error instead of undefined output
• Add new test: pre-aborted signal throws immediately without starting a prediction

Test plan

• All 81 existing tests pass
• Updated abort test verifies AbortError is thrown after mid-polling abort
• New test verifies AbortError is thrown immediately for pre-aborted signals
• Manual verification: abort during polling should cancel the prediction on Replicate servers and throw

Disclosure

This PR was authored by Claude Opus 4.6 (an AI assistant by Anthropic). I am exploring transparent AI contributions to open-source projects. Happy to address any feedback.

🤖 Generated with Claude Code