Add comprehensive GitHub Copilot instructions and fix TypeScript build issues

[Copilot]

This PR creates comprehensive GitHub Copilot instructions for the GitArmor repository and fixes critical TypeScript compilation issues that were preventing successful builds.

Changes Made

🔧 Fixed TypeScript Build Issues

• Fixed case sensitivity issues in import statements throughout the codebase
• Changed Logger → logger and Input → input imports to match actual filenames
• Resolved 17 TypeScript compilation errors that were blocking builds
• Build now completes successfully in ~11 seconds

📚 Created Comprehensive Copilot Instructions

Added .github/copilot-instructions.md with exhaustively tested guidance covering:

Bootstrap & Build Process

• Node.js version requirements (v18+, currently v20.19.5)
• Dependency installation (npm install ~5 seconds)
• Build process (npm run build ~11 seconds with TypeScript + ncc bundling)
• All commands tested with proper timeout recommendations (60+ seconds)

Code Quality & Formatting

• Prettier formatting commands (npm run prettier:check/write)
• Security audit workflow (npm audit - documents 4 known moderate vulnerabilities)
• Critical: Documents that npm audit fix breaks the build due to dependency conflicts

Development Workflow

• Environment configuration with .env file setup
• CLI and GitHub Action usage patterns
• Direct execution methods (node ./dist/index.js)

Validation Scenarios
Four comprehensive test scenarios:

1. Build validation with timing expectations
2. Code quality checks with known limitations
3. CLI functionality testing with fake tokens
4. Policy loading verification

Repository Navigation

• Complete directory structure documentation
• Key source file locations and purposes
• Policy file organization and usage

Validation Results

All documented commands have been tested and validated:

• ✅ npm install completes in ~5 seconds
• ✅ npm run build completes in ~11 seconds
• ✅ npm run prettier:check/write works correctly
• ✅ npm run start executes successfully with proper error handling
• ✅ Direct execution via node ./dist/index.js functions as expected
• ✅ Policy loading and configuration parsing works correctly

The instructions include explicit "NEVER CANCEL" warnings with specific timeout values to prevent premature command termination during CI/CD or development workflows.

Before This PR

$ npm run build
# Failed with 17 TypeScript errors about missing modules

After This PR

$ npm run build
# ✅ Completes successfully in ~11 seconds
# ✅ Generates dist/index.js (1.6MB) and dist/licenses.txt

Fixes #23.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/repos/dcodx/gitarmor
  • Triggering command: node ./dist/index.js (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.