fix(eq): seed device ID at startup and add device management UI

Fix multi-device EQ auto-switching by calling obtenerDispositivoActual()
during cargarPersistido() to seed the initial device ID. Add device
management modal with rename support, EQ preset editing, and connection
status indicator. Translate device UI keys to all 13 locales.

lib/l10n/app_ja.arb

@@ -627,5 +627,18 @@
     "placeholders": {
       "presetName": {}
     }
-  }
-}
+  },
+  "preNoticeCountdown": "{minutes}分後に開始",
+  "@preNoticeCountdown": {
+    "placeholders": {
+      "minutes": {
+        "type": "int"
+      }
+    }
+  },
+  "eqDeviceEditTitle": "デバイスを編集",
+  "eqDeviceNameLabel": "デバイス名",
+  "eqDeviceNameHint": "例：リビングのスピーカー",
+  "eqDeviceNameConfirm": "保存",
+  "eqDeviceConnected": "接続中"
+}