Modernize repository documentation and governance

[ddtdanilo]

Summary

Modernizes the Personal Altium Library into a documented, verifiable, contributor-friendly open hardware repository.

What changed

• Replaced the legacy README with an English project overview, badges, quick start, engineering warnings, and documentation map.
• Added a verified inventory for all 81 schematic symbols and 106 PCB footprints.
• Added SHA-256/size metadata and dependency-free integrity validation for the binary Altium libraries.
• Added installation, validation, contribution, support, security, conduct, changelog, citation, agent, and Claude documentation.
• Added CERN-OHL-P-2.0 licensing and notice files.
• Added GitHub Actions, Dependabot, CODEOWNERS, issue forms, a PR template, and release-note configuration.

Impact

Users can now install and evaluate the library with clear safety guidance. Contributors have an explicit component-validation workflow, and maintainers receive automated checks for binary integrity, inventory drift, broken local links, and generated files.

Validation

• python3 scripts/validate_repository.py
• python3 -m py_compile scripts/validate_repository.py scripts/update_manifest.py
• YAML parsing for every workflow and form
• git diff --cached --check
• Independent OLE inspection confirming that the documented 81 symbol names and 106 footprint names exactly match the binary libraries