test: replace jasmine browser runner with vitest + jsdom

[tkirda]

Summary

PR-1 of the modernization plan: make the test suite headless and CI-ready without touching src/jquery.autocomplete.js. All 26 original Jasmine specs are ported (31 it() cases), and the legacy spec/ directory (vendored Jasmine 1.3.1 + 2.0.1, runner.html) is removed. Now npm test runs everything headless in ~3s and exits nonzero on failure.

This is intentionally tooling-only — the plugin source is unchanged. Source modernization comes in a later PR after CI is green.

What changed

• Vitest + jsdom: vitest.config.js (jsdom env), test/setup.js attaches a single jQuery instance to globalThis / window, registers jquery-mockjax, then loads the UMD plugin so it binds to the same instance.
• Specs ported: test/autocomplete.test.js — beforeEach(done) → await new Promise(...), spyOn → vi.spyOn. Same behavioral coverage as the originals.
• Dependencies: added vitest@4.1.6, jsdom@29.1.1, jquery@3.7.1, jquery-mockjax@2.6.0 as dev deps. jQuery and mockjax versions match what spec/runner.html loaded from CDN.
• Scripts: added npm test and npm run test:watch; broadened lint / format globs to include test/.
• ESLint config rename: eslint.config.js → eslint.config.mjs to silence Node's ESM-reparse warning without adding "type": "module" to package.json (that would break CommonJS consumers of the dist UMD bundle).
• Removed: spec/ directory in full.
• Docs: new CLAUDE.md with project shape, commands, test setup, release flow, non-obvious architecture, and a Conventional Commits requirement for future work.

Notes worth flagging in review

• pool: "threads" is pinned in vitest.config.js — Vitest 4's default forks pool on Windows times out the worker handshake when the setup file does heavy synchronous work (jQuery + mockjax + UMD plugin load). Comment in the config explains. Don't switch pools without re-verifying.
• grunt + grunt-contrib-uglify still in devDependencies. They go away in PR-2 (build refresh). Most of the open npm audit advisories trace back to those — not worth touching here.
• No source changes — src/jquery.autocomplete.js is untouched.

Test plan

• npm test — 31/31 pass, ~3s
• npm run lint — clean
• npm run format — no diffs
• Reviewer sanity-checks no spec was dropped during the port (count went 26 → 31 because some originals tested multiple assertions in one it; a few were split where it read better)

🤖 Generated with Claude Code

[gongph]

这是来自QQ邮箱的假期自动回复邮件。你好，我最近正在休假中，无法亲自回复你的邮件。我将在假期结束后，尽快给你回复。