feat(03-01): extend Progress type, add LessonPhase, update rate limits

- Progress: added totalCorrect, totalErrors, errorKeyCounts, lastPlayedLevels
- New LessonPhase type: discover | practice | words
- Rate limits: 10 text / 5 image per day (was 1 each)
- Updated screens.ts with new Progress field defaults
- Updated existing tests for new rate limits and Progress shape

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ui/screens.ts

@@ -70,6 +70,10 @@ export function initWelcomeScreen(
 			sessionDates: [],
 			selectedCharacter: selectedCompanion,
 			selectedLayout: selectedLayout,
+			totalCorrect: 0,
+			totalErrors: 0,
+			errorKeyCounts: {},
+			lastPlayedLevels: [],
 		};
 		await saveProgress(db, progress);
 		navigateTo("forest");