Deprecate pin-header invert in favor of explicit connection direction

[seveibar]

Summary

• mark the legacy invert option as deprecated in schema metadata
• expose the deprecation in editor tooling for the fluent .invert() builder
• direct pin-header users to connectsFromAbove or connectsFromBelow
• stop the deprecated faceup description from recommending invert

Legacy invert values remain parseable for backward compatibility.

Verification

• targeted compatibility test with the visual-test preload disabled
• bun run build
• bunx biome check src/footprinter.ts src/helpers/zod/base_def.ts tests/invert-deprecation.test.ts