chore(snap): the Store's description says what the app does now

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

snap/snapcraft.yaml

@@ -14,9 +14,20 @@ base: core24
 adopt-info: halkyon-learn # the version, from the app's pubspec.yaml
 summary: Learn with flashcards, studied offline and synced between your devices
 description: |
-  Halkyon Learn is a spaced-repetition learning app: studysets of flashcards with
-  rich text, notes, learning paths and PDFs, reviewed on an FSRS schedule. It works
-  offline and syncs between your devices.
+  Halkyon Learn is a spaced-repetition app for your own material: studysets of
+  flashcards, notes, learning paths and PDFs, reviewed on an FSRS schedule. It
+  works offline and syncs between your devices through an instance anyone can
+  run.
+
+  Learn from what you watch: play films and shows from your Jellyfin server,
+  and every subtitle line is split into dictionary words, with readings above
+  and the translation below. Tap a word, and it is a flashcard.
+
+  Dictionaries for Japanese, Chinese, Korean, German, Greek and English; kanji,
+  hanzi and Hangul written by hand, each stroke checked; exam plans for the
+  JLPT, HSK and Korean levels, with a daily pace to your exam's date; and
+  studysets published to Explore and copied, later releases coming in as
+  merges that keep your own edits.
 
   It starts with an anonymous account; signing in with GitHub later keeps
   everything. It connects to learn.halkyon.eu, the project's instance.