docs: fix broken references and update paths

- Update README.md to remove references to deleted migration/deployment docs
- Fix CONTRIBUTING.md to point to correct documentation paths
- Remove broken references in API.md to non-existent files
- Update ENVIRONMENT_VARIABLES.md to reference existing documentation
- Ensure all documentation links work correctly after reorganization

README.md

@@ -775,16 +775,9 @@ For comprehensive documentation, visit **[`docs/README.md`](docs/README.md)** wh
 - [Code Quality](docs/development/CODE_QUALITY.md) - Quality standards & tools
 - [Application Security](docs/development/APPLICATION_SECURITY.md) - App security practices
 
-#### 🚢 Deployment
+#### 🔧 Implementation
 
-- [Deployment Guide](docs/deployment/DEPLOYMENT.md) - General deployment
-- [Docker Configuration](docs/deployment/DOCKER_IMAGE_CONFIGURATION.md) - Docker setup
-- [Gitea Setup](docs/deployment/GITEA_SETUP.md) - CI/CD configuration
-
-#### 🔄 Migration Guides
-
-- [NodeJS Pre-commit Migration](docs/migration/NODEJS_PRECOMMIT_MIGRATION.md) - Modern git hooks
-- [Buildx Migration](docs/migration/BUILDX_MIGRATION.md) - Docker improvements
+- [Implementation Summary](docs/implementation/IMPLEMENTATION_SUMMARY.md) - Current features and status
 
 ## 📚 Additional Resources
 
@@ -837,10 +830,9 @@ bun test-production.js
 
 ### **Project Documentation**
 
-- **[Code Quality Guide](docs/CODE_QUALITY.md)** - Code formatting, linting, and pre-commit hooks setup
-- **[Security Guide](docs/SECURITY.md)** - Security best practices and configuration
-- **[Deployment Guide](docs/DEPLOYMENT.md)** - Production deployment instructions
-- **[API Documentation](docs/API.md)** - Complete API reference
+- **[Code Quality Guide](docs/development/CODE_QUALITY.md)** - Code formatting, linting, and pre-commit hooks setup
+- **[Security Guide](docs/development/APPLICATION_SECURITY.md)** - Security best practices and configuration
+- **[API Documentation](docs/development/API.md)** - Complete API reference
 - **[Contributing Guide](CONTRIBUTING.md)** - Development guidelines and contribution process
 - **[License](LICENSE)** - MIT license and third-party attributions
 - **[Changelog](CHANGELOG.md)** - Version history and release notes