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>

pubspec.lock

@@ -70,11 +70,24 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "6.0.0"
+  flutter_localizations:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_test:
     dependency: "direct dev"
     description: flutter
     source: sdk
     version: "0.0.0"
+  intl:
+    dependency: transitive
+    description:
+      name: intl
+      sha256: "3df61194eb431efc39c4ceba583b95633a403f46c9fd341e550ce0bfa50e9aa5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.20.2"
   leak_tracker:
     dependency: transitive
     description: