feat(settings): redesign the remove-encryption (decrypt) modal onto reference design

Migrate App::renderDecryptWalletDialog ("Remove Wallet Encryption") onto the
settings-modal reference design — presentation-only for a fund-critical dialog,
plus one deliberate secret-hygiene addition:

- struct-form BeginOverlayDialog(OverlayDialogSpec{BlurFloat, cardWidth 480,
  idSuffix "decrypt"}) replacing the legacy positional overload
- Phase 0 amber TextWrapped warning -> material::DialogWarningHeader(decrypt_warning)
- drop the redundant Phase 0 Separator
- every rendered-chrome string across all 4 phases (PassphraseEntry / Working /
  Success / Error) -> TR() (14 new decrypt_*/try_again keys added to the English
  source + all 8 res/lang/*.json additively; the button reuses
  settings_remove_encryption, the label reuses change_pass_current, cancel/close reused)
- HARDENING: wipe decrypt_pass_buf_ on BlurFloat dismiss (X/Esc/outside-click),
  mirroring the change-passphrase fix; canClose() gates pOpen so this cannot fire
  during the Working phase

The fund-moving async worker pyramid (unlock -> export -> stop -> backup ->
restart -> re-import, vault/PIN cleanup) is byte-for-byte unchanged; the three
in-worker toast notifications and the "Incorrect passphrase" status are left in
English to avoid touching the fund path (a separate service-layer i18n pass).

Verified: build + ctest + hygiene clean; i18n complete in 8 langs with no format
specifiers and the wallet.dat.encrypted.bak literal preserved; a 3-lens adversarial
review (secret-hygiene / fund-path-untouched / ui-i18n) returned zero findings, with
the fund-path lens proving the async pyramid diffs IDENTICAL against HEAD.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

res/lang/es.json

@@ -333,6 +333,19 @@
     "date": "Fecha",
     "date_label": "Fecha:",
     "debug_logging": "REGISTRO DE DEPURACIÓN",
+    "decrypt_desc": "Se exportará el monedero, se reiniciará el daemon con un monedero nuevo sin cifrar y se reimportarán todas las claves. Esto puede tardar varios minutos según el tamaño del monedero.",
+    "decrypt_error_title": "Error al descifrar",
+    "decrypt_step_backup": "Respaldando el monedero cifrado",
+    "decrypt_step_export": "Exportando las claves del monedero",
+    "decrypt_step_restart": "Reiniciando el daemon",
+    "decrypt_step_stop": "Deteniendo el daemon",
+    "decrypt_step_unlock": "Desbloqueando el monedero",
+    "decrypt_success_desc": "Tu monedero ahora está sin cifrar. Se guardó una copia de seguridad del monedero cifrado como wallet.dat.encrypted.bak en tu directorio de datos.",
+    "decrypt_success_title": "¡Monedero descifrado correctamente!",
+    "decrypt_title": "Quitar el cifrado del monedero",
+    "decrypt_wait_general": "Espera. El daemon está exportando claves, reiniciando y reimportando. Esto puede tardar varios minutos.",
+    "decrypt_wait_restart": "Esperando a que el daemon termine de iniciarse...",
+    "decrypt_warning": "Esto quitará el cifrado de tu monedero. Tus claves privadas se almacenarán sin protección en el disco.",
     "delete": "Eliminar",
     "delete_blockchain": "Eliminar Blockchain",
     "delete_blockchain_confirm": "Eliminar y Resincronizar",
@@ -1269,6 +1282,7 @@
     "transfer_to": "Transferir a:",
     "transparent": "Transparente",
     "transparent_address": "Dirección Transparente",
+    "try_again": "Reintentar",
     "tt_addr_url": "URL base para ver direcciones en un explorador de bloques",
     "tt_address_book": "Administrar direcciones guardadas para envío rápido",
     "tt_auto_lock": "Bloquear billetera después de este tiempo de inactividad",