devOps: consolidate devDependencies, replace jest with node:test and …

[modesty]

…bump engine version to the current lowest LTS version 22.23.2

• Test Runner Migration: Replaced Jest with Node built-in node:test and node:assert/strict across
  all 7 test suites (74 tests), eliminating ~250 transitive dependencies and reducing test execution time
  from ~13s to ~1.6s.
• Test Timeouts & Discovery: Restored bounded 15-second timeouts (--test-timeout=15000) for event-
  based tests and used explicit test file paths to ensure reliable cross-platform (macOS/Linux/Windows)
  discovery.
• Code Coverage & Exclusions: Configured native Node coverage generating dual console spec tables and
  coverage/lcov.info, excluding test/base/generated files via --test-coverage-exclude.
• Node Engine Bump: Bumped engines.node to >=22.23.2 and updated @types/node to ^22.20.2 to
  resolve Node 20 V8 coverage sourcemap mapping crashes and align with the active LTS baseline.
• Dependency Consolidation: Replaced separate @typescript-eslint/eslint-plugin and @typescript- eslint/parser with unified typescript-eslint, and removed dead packages (jest, @rollup/plugin- commonjs, @rollup/plugin-node-resolve, @rollup/plugin-eslint, resolutions, overrides).
• Build & Sourcemaps: Restored sourcemap: true in Rollup to eliminate @rollup/plugin-typescript
  build warnings, and removed unused json() plugin from CLI bundle.
• TypeScript Declaration Fix: Implemented declaration merging in .d.cts (export = PDFParser) so
  CommonJS TypeScript consumers construct without TS2351.
• CI & Scripts: Modernized GitHub Actions workflow with a multi-OS matrix (ubuntu-latest, windows- latest) using npm ci for reproducible clean builds, and updated test/p2j.one.sh to enforce exit 1 on unexpected exit code mismatches.