add language learner project

Dutch and Korean (explained in English) and English (explained in Dutch)
from A1 to C1, with a Hangul level for Korean. Lessons with notes, words
and sentences generate multiple-choice, typing, sentence building, cloze,
listening and matching exercises. Endless challenges: a seeded daily
challenge, sprint, survival, mixed practice, level tests, spaced-repetition
reviews and generated drills (numbers, clock times, de/het, plurals, Dutch
and Korean conjugation, particles, Hangul reading, irregular verbs).
Progress is stored in localStorage with export/import.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/routes/projects/language-learner/+page.server.ts

@@ -0,0 +1,20 @@
+import { allEntries, allLessons } from '$lib/language-learner/course';
+import { COURSES, loadCourse } from '$lib/language-learner/courses';
+import type { PageServerLoad } from './$types';
+
+// Counted on the server so the overview doesn't download three full courses.
+export const load: PageServerLoad = async () => {
+	const courses = await Promise.all(COURSES.map((c) => loadCourse(c.code)));
+	return {
+		counts: Object.fromEntries(
+			courses.map((c) => [
+				c.code,
+				{
+					lessons: allLessons(c).length,
+					words: allEntries(c).filter((e) => e.kind === 'word').length,
+					levels: c.levels.map((lv) => lv.band)
+				}
+			])
+		) as Record<string, { lessons: number; words: number; levels: string[] }>
+	};
+};