Add Component-Footprint Lookup & Validation Tools

[lamaalrajih]

Description

This PR delivers two new capabilities:

1. Component-Footprint Lookup & Validation – search .pretty libs, validate footprints, return metadata.
2. Supplier-Lookup Tools – async real-time part search / detail / batch availability via Mouser & Digi-Key (aiohttp, 10s timeout, retries, 24 h on-disk cache, progress callbacks).

Related Issue(s)

n/a

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Performance improvement
• Code refactoring (no functional changes)
• Other (please describe):

Testing Performed

• Added new unit tests
• Manually tested on macOS
• Manually tested on Windows
• Manually tested on Linux
• Integration tested with Claude Desktop or other MCP client

Checklist

• My code follows the project's coding style
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation to reflect my changes
• My changes generate no new warnings or errors
• I have checked that my changes work on all supported platforms
• New and existing unit tests pass with my changes

Additional Notes

Optional on-disk JSON index framework is sketched but not enabled; can be added later for performance.

After pulling, run pip install -r requirements.txt and set DIGIKEY_API_KEY / MOUSER_API_KEY in your shell or env secrets.