add JLCPCB footprint autocomplete

[techmannih]

Summary

• add a JLCPCB autocomplete generator that builds lib/generated/jlcpcb-autocomplete.ts from the public jlcsearch API
• export the generated JLCPCB path type and include it in FootprintProp
• allow jlcpcb: footprint selectors in pcbSx and update the footprint autocomplete type test
• add a package script for regenerating the JLCPCB autocomplete dataset

Why

JLCPCB footprint source strings were missing from the typed autocomplete/export surface, so consumers could not get first-class type support for jlcpcb: footprint references.

Impact

Consumers can now use jlcpcb:C... footprint references with autocomplete/type safety, including footprint props and the matching pcbSx selector path.

Validation

• bun scripts/generate-component-types.ts
• bun scripts/generate-manual-edits-docs.ts
• bun scripts/generate-readme-docs.ts
• bun scripts/generate-props-overview.ts
• bun scripts/generate-jlcpcb-autocomplete.ts
• bun test
• bun run typecheck
• bun run format:check