test: add unit and integration test suite
Add 34 tests (27 unit, 7 integration) using node:test runner:
Unit tests:
- pickServer(), findRoot(), pathToUri(), uriToPath()
- isLspCommand(), listCommands()
- formatHover(), formatDefinition(), formatReferences(), formatDiagnostics()
Integration tests:
- daemon lifecycle (status/stop) on isolated socket
- CLI --no-daemon queries (hover, documentSymbol, diagnostics)
Supporting changes:
- socketPath() honors PI_LSP_SOCKET_PATH env var for test isolation
- test fixtures for valid and broken TypeScript files
- npm test / test:unit / test:integration scripts
Evan Reichard
aa7309b363