feat(app): show and write a word's senses with their grammar

A word with senses (as a dictionary gives them) shows them when its
answer shows: numbered when there are several, each with its label, its
translations and its grammar codes, small and slanted, their meaning on
hover. A word usually written in kana shows its reading from the start:
its kanji are rarely seen, so there is nothing to hide. The composer
writes the senses' translations, adds and removes senses, and keeps the
codes as they came.

The codes' short forms and meanings are the dictionary's own English
(JMdict's entities), kept as data beside the cards.

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

halkyon_learn_flutter/lib/l10n/app_en.arb

@@ -496,6 +496,11 @@
   "vocabularyMeaningHint": "Meaning",
   "vocabularyAddMeaning": "Add meaning",
   "vocabularyRemoveMeaning": "Remove meaning",
+  "vocabularyGlossHint": "Translation",
+  "vocabularyAddGloss": "Add translation",
+  "vocabularyRemoveGloss": "Remove translation",
+  "vocabularyAddSense": "Add sense",
+  "vocabularyRemoveSense": "Remove sense",
   "matchingCategories": "Categories",
   "matchingCategoriesHint": "The drop-zone cards learners drag items onto. Each category needs at least one item, so a card can't have more categories than items.",
   "matchingCategory": "Category {number}",