EXPERIMENTAL: Multilanguage Swipe Typing Support

- Primary language selection (6 bundled: EN, ES, FR, PT, IT, DE)
- Secondary language for bilingual predictions (true bilingual, not just accent recovery)
- Per-language custom word dictionaries (custom words now language-specific)
- Per-language disabled words lists
- Downloadable language packs (NL, ID, MS, SW, TL)
- Configurable secondary language weight slider (0.5x-1.5x)
- Auto language detection with sensitivity slider
- Neural network predicts from BOTH primary and secondary dictionaries
- Custom words now available in swipe (NN) pipeline
- Android user dictionary filtered by locale (prevents cross-language contamination)
- Language-specific contraction support (French c'est, Italian l'uomo, etc.)

Note: NN outputs 26 English letters; dictionaries provide accent recovery (cafe -> cafe)
