test: Add comprehensive CLA validation tests and fix Jest environment

.gitignore

@@ -5,3 +5,4 @@ lib
 .idea
 codeql-db*
 results.sarif
+*.tsbuildinfo

TYPESCRIPT_CONFIG.md

@@ -0,0 +1,114 @@
+# TypeScript Configuration Guide
+
+This project uses a **single, simplified TypeScript configuration** optimized for both VSCode developer experience and clean production builds.
+
+## Configuration Philosophy
+
+Following the upstream [contributor-assistant/github-action](https://github.com/contributor-assistant/github-action) pattern with improvements:
+- ✅ Single `tsconfig.json` (matches upstream simplicity)
+- ✅ VSCode recognizes Jest types in test files (no red squiggles!)
+- ✅ Production builds compile only `src/` files (clean output)
+- ✅ Enhanced with `@types/jest` for full IntelliSense (improvement over upstream)
+
+## Configuration File
+
+### 📁 `tsconfig.json` (Universal Config)
+- **Purpose**: IDE support and type checking for all files
+- **VSCode**: Sees all files including tests with Jest types
+- **Build**: Command-line flags ensure only `src/` compiles
+- **Types**: Node.js + Jest for full IDE support
+- **Used by**:
+  - VSCode TypeScript language server (checks everything)
+  - Build script (compiles only src/ via CLI args)
+  - Jest via ts-jest transformer
+
+**Key settings:**
+```json
+{
+  "compilerOptions": {
+    "types": ["node", "jest"]     // IDE recognizes Jest globals everywhere
+  },
+  "exclude": ["node_modules", "dist", "lib"]  // Build artifacts only
+}
+```
+
+**Build command:**
+```json
+{
+  "scripts": {
+    "build": "tsc --rootDir src --outDir lib src/**/*.ts && ncc build"
+  }
+}
+```
+- `--rootDir src`: Sets source root for path resolution
+- `src/**/*.ts`: Only compile source files (not tests)
+- `--outDir lib`: Output to lib directory
+
+## Scripts
+
+```bash
+# Production build (only src/ compiled to lib/)
+npm run build
+
+# Run tests (uses same tsconfig.json)
+npm test
+
+# Type check everything including tests
+npx tsc --noEmit
+```
+
+## Benefits
+
+✅ **VSCode IntelliSense**: No "Cannot find name 'jest'" errors in test files
+✅ **Clean Builds**: Only `src/` files compiled to `lib/` directory
+✅ **Upstream Compatible**: Single config matches contributor-assistant/github-action
+✅ **Clean Production Builds**: Tests excluded via `exclude` and `rootDir`
+✅ **Superior IDE Support**: @types/jest eliminates "Cannot find name 'jest'" errors
+✅ **Simple Maintenance**: Single config file to manage
+✅ **CI/CD Compatible**: Node.js matrix builds work without modification
+
+## Improvements Over Upstream
+
+While matching upstream's single-config approach, we include:
+1. **`@types/jest`** in devDependencies (VSCode IntelliSense for tests)
+2. **`jest`** package in devDependencies (not in upstream)
+3. **`types: ["node", "jest"]`** in tsconfig.json (prevents IDE errors)
+
+## VSCode Configuration
+
+The `.vscode/settings.json` is configured to:
+- Use workspace TypeScript version
+- Recognize Jest command for test execution
+- Exclude compiled files and node_modules from search
+
+## Dependency Organization
+
+### Production Dependencies (`dependencies`)
+```json
+{
+  "@actions/core": "Runtime GitHub Actions core",
+  "@actions/github": "Runtime GitHub API access",
+  "@octokit/rest": "Runtime REST API client",
+  "lodash": "Runtime utility library"
+}
+```
+
+### Development Dependencies (`devDependencies`)
+```json
+{
+  "@types/jest": "Jest type definitions",
+  "@types/node": "Node.js type definitions",
+  "jest": "Test framework",
+  "ts-jest": "TypeScript transformer for Jest",
+  "typescript": "TypeScript compiler",
+  "@vercel/ncc": "Production bundler"
+}
+```
+
+## How It Works
+
+1. **VSCode** loads `tsconfig.json` → sees everything, no errors
+2. **`npm run build`** runs `tsc` → compiles only `src/` (via `rootDir`), excludes tests
+3. **`npm test`** runs Jest with ts-jest → uses same tsconfig.json
+
+This setup matches the upstream GitHub Action project structure while providing better developer experience through proper type definitions.