feat(01-05): forest screen with level map and complete app flow

- Add forest overview screen with 6-level map showing locked/current/completed states
- Create src/forest/scene.ts with getLevelStatus, renderLevelMap, initForestScreen
- Wire complete flow: welcome -> forest -> lesson -> forest with progress updates
- Add forest CSS with level card styles and continue button

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

src/app.ts

@@ -1,6 +1,7 @@
-import type { ScreenName, KeyboardLayout } from "./types";
+import type { ScreenName } from "./types";
 import { openDB, getProgress, saveProgress } from "./storage/db";
 import { initWelcomeScreen, initLessonScreen } from "./ui/screens";
+import { initForestScreen } from "./forest/scene";
 
 let db: IDBDatabase;
 let lessonCleanup: (() => void) | null = null;
@@ -19,46 +20,56 @@ export function getDB(): IDBDatabase {
 	return db;
 }
 
-export async function startLesson(
-	level: number,
-	layout: KeyboardLayout,
-): Promise<void> {
+async function handleLessonComplete(completedLevel: number): Promise<void> {
+	// Update progress after lesson completion
+	const progress = await getProgress(db);
+	if (!progress) return;
+
+	// Add level to completedLevels if not already there
+	if (!progress.completedLevels.includes(completedLevel)) {
+		progress.completedLevels.push(completedLevel);
+	}
+
+	// Advance to next level if this was the current level (LEVL-02, LEVL-03)
+	if (completedLevel === progress.currentLevel) {
+		progress.currentLevel = completedLevel + 1;
+	}
+
+	// Increment session count
+	progress.totalSessions++;
+
+	// Add today's date if not already recorded
+	const today = new Date().toISOString().split("T")[0]!;
+	if (!progress.sessionDates.includes(today)) {
+		progress.sessionDates.push(today);
+	}
+
+	await saveProgress(db, progress);
+
+	// Re-init forest screen with updated progress, then navigate
+	await initForestScreen(db, startLessonFromForest);
+	showScreen("forest");
+}
+
+function startLessonFromForest(level: number): void {
 	// Clean up previous lesson if any
 	if (lessonCleanup) {
 		lessonCleanup();
 		lessonCleanup = null;
 	}
 
-	showScreen("lesson");
+	// Get layout from progress (already loaded)
+	getProgress(db).then((progress) => {
+		const layout = progress?.selectedLayout ?? "de";
 
-	lessonCleanup = initLessonScreen(db, level, layout, async (completedLevel: number) => {
-		// Update progress after lesson completion
-		const progress = await getProgress(db);
-		if (!progress) return;
+		showScreen("lesson");
 
-		// Add level to completedLevels if not already there
-		if (!progress.completedLevels.includes(completedLevel)) {
-			progress.completedLevels.push(completedLevel);
-		}
-
-		// Advance to next level if this was the current level (LEVL-02, LEVL-03)
-		if (completedLevel === progress.currentLevel) {
-			progress.currentLevel = completedLevel + 1;
-		}
-
-		// Increment session count
-		progress.totalSessions++;
-
-		// Add today's date if not already recorded
-		const today = new Date().toISOString().split("T")[0]!;
-		if (!progress.sessionDates.includes(today)) {
-			progress.sessionDates.push(today);
-		}
-
-		await saveProgress(db, progress);
-
-		// Navigate to forest (per D-07: skip reward in Phase 1)
-		showScreen("forest");
+		lessonCleanup = initLessonScreen(
+			db,
+			level,
+			layout,
+			handleLessonComplete,
+		);
 	});
 }
 
@@ -66,11 +77,17 @@ export async function initApp(): Promise<void> {
 	db = await openDB();
 	const progress = await getProgress(db);
 	if (progress && progress.selectedCharacter) {
-		// Returning user -- go to forest
+		// Returning user -- init forest and go there
+		await initForestScreen(db, startLessonFromForest);
 		showScreen("forest");
 	} else {
-		// First time -- show welcome
-		initWelcomeScreen(db, showScreen);
+		// First time -- show welcome, then forest after setup
+		initWelcomeScreen(db, async (screen: ScreenName) => {
+			showScreen(screen);
+			if (screen === "forest") {
+				await initForestScreen(db, startLessonFromForest);
+			}
+		});
 		showScreen("welcome");
 	}
 }