v2.0.0: Node 22+/NestJS 11–12 support, Vitest, and close() fix

[rbonestell]

This pull request targets the current LTS lines of Node.js and the maintained NestJS majors, fixes two defects, switches the test suite from Jest to Vitest, and removes the example app. It is a breaking change: 2.0.0, because it drops support for Node 18/20 and NestJS 9/10.

Breaking changes:

• engines.node is now >=22.0.0. Node 18 and 20 are end-of-life; 22 and 24 are the current LTS lines.
• peerDependencies["@nestjs/common"] is now ^11.0.0 || ^12.0.0. NestJS 9 and 10 are no longer supported.

Fixes:

• close() now calls server.close() before closeAllConnections(). Previously the proxy kept listening and accepting connections after close() and kept the process alive. A side effect is that start() works again after close().
• Build output now matches main/types again. The build had started emitting dist/src/... and dist/test/..., so the next release would have been unusable (1.2.0 on npm is fine). The new tsconfig.build.json compiles only lib/src, and the package again contains exactly three dist/ files.

NestJS 12 compatibility:

• NestJS 12 ships as ES modules only. The library is still CommonJS, and INestApplication is now imported with import type, so the emitted JS has no runtime dependency on @nestjs/*. This was verified with real HTTPS requests on NestJS 11 and 12, Express and Fastify, and Node 22 and 24, plus a TypeScript consumer type-check (nodenext and bundler).
• Removed the unreachable else if condition in start() (it's now a plain else; behavior is identical).

Testing:

• Switched from Jest to Vitest 5 with v8 coverage. Jest can only load the ES-module-only NestJS 12 packages on Node 24.9+, and only with --experimental-vm-modules. The spec changes are only the jest.* → vi.* renames.
• Coverage is enforced at 100% (lines, branches, functions, statements). The earlier 100% report from Jest 29/ts-jest was inaccurate; the real branch coverage was 95.65%, and the missed branch was the dead else if above.
• Added tests for close() stopping the server and for close() doing nothing when the proxy isn't listening.
• The test workflow runs a Node 22/24 × NestJS 11/12 matrix. NestJS 11 is installed with npm install --no-save over the NestJS 12 dev dependencies.

Dependencies and repo:

• Dev dependencies: NestJS 12 and @types/node 22; added vitest and @vitest/coverage-v8; removed jest, ts-jest, @types/jest, ts-node, and @nestjs/testing (unused).
• lint-staged moved from dependencies to devDependencies, so consumers no longer install it.
• Removed the example/ app.
• CI now uses Node 22/24 for build and test and Node 24 for publish. The workflows now also trigger on changes to lib/test/**, package-lock.json, and tsconfig.build.json.
• Added AGENTS.md (with CLAUDE.md symlinked to it) and replaced the Jest references in the README badge and VS Code config.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (e32f927) to head (3275913).

Additional details and impacted files

@@            Coverage Diff            @@
##              main        #9   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           38        35    -3     
  Branches         8         7    -1     
=========================================
- Hits            38        35    -3     

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