feat: migrate compile action to TypeScript/Node.js

[ronaldtse]

Summary

Migrate the compile action from a composite action (shell script wrapper) to a TypeScript/Node.js action with architectural parity to sibling actions (cache, site-gen).

Changes

New Features

• Type-safe input handling with validation
• Unit tests with Vitest (38 tests, 80% coverage threshold)
• Output capture (metanorma-version, output-dir)
• Input validation (path traversal protection)
• Version-aware command building

Files Created

• src/main.ts - Entry point
• src/input-helper.ts - Input parsing and validation
• src/compile-settings.ts - TypeScript interface for 14 inputs
• src/compile-command-manager.ts - Command building for metanorma compile
• src/compile-provider.ts - Main orchestration logic
• src/version-helper.ts - Version class with semver comparison
• src/fs-helper.ts - Directory existence helper
• src/state-helper.ts - IsPost state management
• __test__/*.test.ts - 4 test files with 38 tests
• package.json, tsconfig.json, eslint.config.js, vitest.config.ts
• dist/index.js - Bundled action

Files Modified

• action.yml - Changed from using: composite to using: node24, added outputs
• .github/workflows/test.yml - Use shared workflows, added input validation tests

Verification

• Unit tests: 38 tests passing
• Build: dist/index.js created (423KB minified)
• Lint: No errors
• Format: Prettier passes

Test Plan

• Verify lint-test job passes
• Verify test-compile-packed-mn passes on all platforms
• Verify test-compile-bundler passes
• Verify test-compile-docker passes
• Verify test-input-validation catches path traversal
• Verify test-outputs sets metanorma-version correctly