ChemSearch v1.13.1 - Release build hotfix

Improvements & Fixes

• Fixed Chemical Database showing empty categories in release builds.
• Fixed crashes when opening favorited compounds.
• Fixed crashes when opening downloaded compounds.
• Improved recovery for saved favorites, downloads, and recent searches affected by older broken release data.

Technical Changes

• Added R8 keep rules for Gson-backed ChemSearch data models.
• Kept Gson generic type information and annotations needed for JSON parsing.
• Kept ViewModel classes stable for release-build creation.
• Hardened saved compound and offline download loading so malformed saved records are skipped or repaired instead of crashing the app.