bug(core): onCapture callback errors in capture.ts are silently swallowed #276

Summary

In packages/core/src/capture.ts, the onCapture callback is invoked after a capture completes. If the callback throws (or returns a rejected promise in an async case), the error is silently lost — no console warning, no re-throw, no way for the caller to detect the failure.

Root cause

The capture handler invokes options.onCapture(packet, selection) without wrapping it in a try/catch, and without awaiting the return value if the callback is async.

Impact

• Silent data loss: if onCapture is async and fails (e.g. a network POST fails), the user's capture attempt appears to succeed
• No way to surface errors to the UI for a retry or error state

Fix

Wrap the call and surface errors through a documented onError channel:

try {
  await options.onCapture?.(packet, selection);
} catch (err) {
  options.onError?.(err instanceof Error ? err : new Error(String(err)));
}

onError should be added to the capture options type to give callers a standard error handler.