feat: add copy note content option and migrate AGENTS.md to CLAUDE.md

Add a "Copy note content" option to the note options menu that copies the
event's content field to clipboard. Merge AGENTS.md into CLAUDE.md with
enhanced i18n rules emphasizing append-only locale key ordering.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/i18n/locales/it.ts

@@ -683,6 +683,7 @@ export default {
       'Soglia predefinita del filtro del punteggio di fiducia ({{n}}%)',
     'No notes found': 'Nessuna nota trovata',
     'Try again later or check your connection': 'Riprova più tardi o controlla la connessione',
-    'Hide indirect': 'Nascondi indirette'
+    'Hide indirect': 'Nascondi indirette',
+    'Copy note content': 'Copia contenuto della nota'
   }
 }