Implement comprehensive localization framework with English and Finnish support

- Add flutter_localizations dependency and l10n configuration
- Create ARB files for English (en) and Finnish (fi) translations
- Localize UI strings across all major components:
  * Navigation drawer and page titles
  * Scoring interface (arrows per end, ruleset names)
  * Scorecard headers (End, Arrows, Sum of 3/6, Accumulative)
  * Keypad functional buttons (CLEAR/TYHJENNÄ, CLOSE/SULJE)
  * Settings page placeholder content
  * Dialog messages and confirmation prompts
- Preserve universal archery scoring notation (X, 10, 9, M remain unlocalised)
- Use authentic Finnish archery terminology throughout
- Configure main app with proper localization delegates and supported locales
- Generate localization classes automatically via flutter_localizations

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

l10n.yaml

@@ -0,0 +1,6 @@
+# Flutter localization configuration
+arb-dir: lib/config/localization
+template-arb-file: app_en.arb
+output-localization-file: app_localizations.dart
+output-class: AppLocalizations
+output-dir: lib/config/localization/generated