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/+page.svelte

@@ -10,6 +10,7 @@
 		{ name: 'cs prices', href: '/projects/cs-prices', external: false },
 		{ name: 'osu! map finder', href: '/projects/spotify-beatmap-finder', external: false },
 		{ name: 'game tracker', href: '/projects/game-tracker', external: false },
+		{ name: 'language learner', href: '/projects/language-learner', external: false },
 		{ name: 'money tracker', href: '/projects/money-tracker', external: false },
 		{ name: 'world opinions', href: '/projects/world-opinions', external: false },
 		{ name: 'vash esports', href: 'https://esports.vash.software', external: true },