Rename the darker tone to AMOLED; file icons are always colored

- Tone: the "darker" option is labelled "AMOLED" in all 7 locales — it is
  the true-black AMOLED palette. The persisted value stays "darker", so no
  settings migration.
- File icons: the Plain/Multi option is gone and the per-category glyphs +
  colors are always on. Removed the iconColors setting (type, default,
  signal, setter, options row, strings) and the plain branch in
  file-icons.ts. A stale "iconColors" key in settings.json is carried
  harmlessly and dropped on the next save.

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

src/shared/i18n/es.ts

@@ -34,7 +34,7 @@ export const es = {
 		language: "Idioma",
 		system: "Sistema",
 		theme: { label: "Tema", system: "Sistema", light: "Claro", dark: "Oscuro" },
-		tone: { label: "Tono", dark: "Oscuro", darker: "Más oscuro" },
+		tone: { label: "Tono", dark: "Oscuro", darker: "AMOLED" },
 		accent: { label: "Acento" },
 		accentNames: {
 			graphite: "Grafito",
@@ -46,7 +46,6 @@ export const es = {
 			green: "Verde",
 			teal: "Turquesa",
 		},
-		fileIcons: { label: "Iconos", plain: "Simple", multi: "Color" },
 		interface: { label: "Interfaz", smaller: "Más pequeña", larger: "Más grande", reset: "Restablecer al 100%" },
 		speedUnit: { label: "Unidad de velocidad" },
 		transfers: { label: "Transferencias", single: "Una", multi: "Varias" },