test: add browser tests

[aikoven]

No description provided.

[Copilot]

Pull Request Overview

Adds browser testing support and migrates the test suite from Jest to Mocha with a custom lightweight spying utility.

• Introduces WebdriverIO browser runner configuration and scripts for Chrome/Firefox/Safari.
• Replaces Jest APIs (test, jest.fn, snapshots) with Mocha (it) and the expect library plus a custom spy utility.
• Updates TypeScript configs to exclude new test utilities from build outputs.

Reviewed Changes

Copilot reviewed 13 out of 16 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
wdio.browser.conf.ts	New WebdriverIO config enabling browser-based test runs with per-browser capabilities.
tsconfig.es.json	Excludes tests and test utilities from ES build output.
tsconfig.build.json	Excludes tests and test utilities from CommonJS build output.
src/waitForEvent.test.ts	Migrates Jest tests to Mocha/expect and uses custom spy utility.
src/testUtils/spy.ts	Adds custom spy implementation to replace jest.fn / spyOn.
src/spawn.test.ts	Converts Jest tests (snapshots and mocks) to Mocha with custom spies.
src/race.test.ts	Migrates abort/race behavior tests to Mocha and custom spies.
src/forever.test.ts	Updates forever behavior test to Mocha with spy usage.
src/execute.test.ts	Reimplements extensive execution tests using custom spies.
src/all.test.ts	Migrates aggregate promise tests to Mocha/custom spies.
src/abortable.test.ts	Converts abortable tests to Mocha and spy utility.
src/AbortError.test.ts	Replaces Jest test blocks with Mocha's it.
package.json	Replaces Jest with Mocha/WebdriverIO tooling and adds browser test scripts.

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