refactor: split catalog into individual files per software/config

[kaic]

Summary

Addresses #11 - Splits monolithic software-catalog.js (1584 lines) and configurations.js (1095 lines) into individual files organized by category.

Changes

• Created directory structure: src/data/software/<category>/<item>.js
• Created directory structure: src/data/configurations/<category>/<item>.js
• Extracted 122 software items into individual files
• Extracted 80 configuration items into individual files
• Converted catalog files to aggregators that import all individual files
• Updated CONTRIBUTING.md with new structure and examples

Benefits

• ✅ Prevents merge conflicts when multiple PRs add different software
• ✅ Easier to find and modify specific items
• ✅ Better code organization
• ✅ Each file is small and focused
• ✅ No manual aggregator updates needed - just add file to correct folder

Testing

• Build succeeds (264 modules)
• All software items still appear in UI
• All configurations still appear in UI
• No broken imports

Structure Example

src/data/
├── software-catalog.js (aggregator)
├── configurations.js (aggregator)
├── software/
│   ├── browsers/brave.js
│   ├── development/vscode.js
│   └── ...
└── configurations/
    ├── privacy/disable-telemetry.js
    └── ...

Closes #11