feat(oxibadge): cache employee names locally and let readers be a list

Employee names are now cached locally (employees.toml, keyed by reader
index then employee id) instead of being re-fetched from the time
clock on every month: load_employees only asks the device for ids not
already in the cache. When a month has employees the cache doesn't
know yet, a new screen (NewEmployees.svelte) lets the user name them
before continuing to the review screen; the chosen names are local to
Oxibadge only, never written back to the device. The same cache can be
managed afterwards from a drawer reachable from the time clock card in
Settings ("Gestisci dipendenti"), reusing the rename-in-row pattern
from the original mockup.

Settings.readers is a list again (was flattened to a single `reader`
object) so multiple time clocks can be supported later; only the first
one is used today.

Also:
- buildEmployees() now derives the employee list from the month's
  records instead of from every cached name ever seen, so the review
  screen no longer shows employees unrelated to the selected month.
- Renaming an employee from the review screen's pencil button now
  actually persists to the cache (the callback existed but was never
  wired up).
- Translated to English a number of Rust/TS/Svelte comments that had
  been written in Italian; only the i18n locale files should contain
  Italian.
- Minor dedup: extracted PillButton.svelte (was duplicated inline in
  ReaderCard), promoted the repeated .mono CSS rule to app.css, moved
  initials() out of the review feature into $lib/text.ts.

Assisted-by: Claude Sonnet 5 <noreply@anthropic.com>

oxibadge/src/lib/locales/it.json

@@ -156,6 +156,27 @@
     "save_saving": "Salvataggio…",
     "save_saved": "Modifiche salvate",
     "save_invalid": "Non salvato: correggi l'errore",
-    "save_failed": "Salvataggio non riuscito"
+    "save_failed": "Salvataggio non riuscito",
+    "employees_title": "Dipendenti",
+    "employees_count": "{n, plural, one {1 dipendente} other {{n} dipendenti}}",
+    "manage_employees": "Gestisci dipendenti",
+    "close_aria": "Chiudi",
+    "employee_name_aria": "Nome del dipendente #{id}",
+    "edit_name_aria": "Modifica nome di {name}",
+    "remove_name_aria": "Rimuovi {name} dalla cache",
+    "employee_remove_confirm": "Rimuovere {name}? Al prossimo controllo verrà chiesto di nuovo il nome.",
+    "remove": "Rimuovi",
+    "no_employees_found": "Nessun dipendente trovato.",
+    "employees_local_note": "I nomi modificati valgono solo in Oxibadge: il timbratore non viene mai scritto."
+  },
+  "new_employees": {
+    "title": "Nuovi dipendenti",
+    "subtitle": "{n, plural, one {Sul timbratore c'è 1 dipendente nuovo.} other {Sul timbratore ci sono {n} dipendenti nuovi.}}",
+    "hint": "Correggi i nomi se serve: valgono solo in Oxibadge.",
+    "missing_placeholder": "nome mancante",
+    "name_aria": "Nome del dipendente #{id}",
+    "renamed_count": "{n, plural, one {1 nome modificato} other {{n} nomi modificati}}",
+    "missing_count": "{n, plural, one {1 nome mancante} other {{n} nomi mancanti}}",
+    "continue": "Continua"
   }
 }