feat: add French (fr) localization

[c0detamer]

Description

Adds French localization support to the FaceLiveness package. French-speaking users will see all liveness check UI strings in French automatically when their device language is set to French — no changes required from app developers.

Changes

• Added Sources/FaceLiveness/Resources/fr.lproj/Localizable.strings with French translations for all 38 UI strings
• Updated Package.swift to declare fr.lproj as a processed resource so SPM bundles it at build time

How it works

The existing NSLocalizedString/Bundle.module lookup in String+Localizable.swift already handles locale selection automatically. iOS falls back to Base.lproj (English) for any non-French locale or missing key — no Swift source changes were needed.

Testing

• swift package dump-package confirms fr.lproj is correctly declared with the process rule alongside Base.lproj
• All 38 keys in fr.lproj match exactly the keys in Base.lproj — no missing or extra keys
• Existing English behavior is unaffected; Base.lproj/Localizable.strings is unchanged

Checklist

• French translations cover all existing localization keys
• Base.lproj/Localizable.strings is unmodified
• Package.swift builds without errors
• Tested on a French-locale device/simulator