Fix Xcode warnings

[coffee-cup]

Fixes the current Xcode warning set without changing runtime behavior.

• Marks Core Data factory helpers as @discardableResult where callers intentionally rely on insertion side effects.
• Handles future StoreKit transaction states with @unknown default.
• Makes small explicit-discard/access-level cleanups for number formatting, color conversion, and confetti color defaults.
• Aligns the widget extension build and marketing versions with the containing app so embedded extension validation is clean.
• Root cause: several APIs intentionally return created objects even when some call sites only need the side effect, and the widget target version settings had drifted from the app target.
• Validated with xcodebuild -quiet -scheme bowtie2 -destination 'generic/platform=iOS' clean build CODE_SIGNING_ALLOWED=NO.