[SimonJang]

Summary

• replace Travis and the AVA/XO/NYC toolchain with GitHub Actions and node:test
• add a complete npm lockfile, current package metadata, and a manual-publish test gate
• preserve native synchronous iterable support, including arrays, Sets, generators, and custom iterables
• normalize iteration and serialization failures to stable synchronous errors without console side effects
• verify exact output and completion for arrays, Sets, and generators in the Node 4 smoke test

Compatibility

• preserves version 1.0.1, CommonJS, Node >=4, eager conversion, iteration order, and successful NDJSON output
• retains previously accepted iterable inputs; the modernization's temporary array-only guard has been removed
• non-iterable input, invalid items, and iteration/serialization failures throw Error('Expected every item to be a JSON-serializable object')
• objects that serialize to undefined now fail synchronously instead of producing invalid stream chunks
• preserves manual publishing; this PR does not publish a release
• targets master, which contains the published release; the default development branch is stale

Verification

• Eight tests pass, including exact-output Set/generator and empty-iterable regressions observed failing before the compatibility fix
• Thirty-eight cases compared with the published implementation; all 22 valid-output cases retain identical observable outcomes
• Smoke failure probes reject missing, unfinished, incorrect/truncated streams and stream errors, including when the other inputs succeed
• Package dry-run contains the four intended files
• Publish dry-run runs the eight-test gate without publishing
• Lockfile/dependency checks and git diff --check
• Independent Astra reviews of the error-boundary and iterable-compatibility fixes: no actionable findings
• Hosted Node 22/24/26 tests and Node 4 array/Set/generator smoke pass on 3383f8c46aa675b112f62340504eaac999bab83e

Passing PR workflow