feat: add PrimeTween Free skills

[yany79]

Summary

• add a PrimeTween Free skill module with installation/config inspection and factory discovery
• generate lifecycle-aware Transform tween and Sequence scripts using PrimeTween 1.4.6 APIs
• add PrimeTween-specific advisory guidance, localization, schema-first docs, and module registration
• reconcile published skill/module totals with the actual post-change surfaces

Validation

• Static integration checks for skill discovery, localization, docs, metadata, and published counts
• Cross-checked generated calls against PrimeTween 1.4.6 package source
• Unity 2022.3+/Unity 6 Editor import, HTTP endpoint, and EditMode validation (not available in this isolated checkout)

Notes

PrimeTween is accessed through reflection so UnitySkills remains compilable when the optional com.kyrylokuzyk.primetween package is absent. The module intentionally targets PrimeTween Free; it does not emulate or configure PrimeTween Pro components.

[Besty0728]

Please prioritize merging into our beta branch rather than the main branch.