feat(merge): run per-address consolidation as a paced background job

"Keep in each address" posted one task that called z_mergetoaddress for
every batch of every address back to back; each call is a whole-wallet
scan under cs_main, and the daemon runs the ops one at a time anyway.
It is now an App-owned services::ConsolidationRun:

- one RPC at a time; the next merge only after the previous batch left the
  queue and a gap as long as the last call took (2-120 s);
- pauses while the node syncs, the wallet is locked, a send of ours is in
  progress, or another wallet scan is running;
- failures classified: nothing that may have queued is ever resent; a
  breaker stops after 3 dead addresses or 3 failed ops in a row;
- each merge is charged to the scan budget; one re-read and one forced
  balance at the end;
- it keeps running when the dialog closes: a status-bar chip, a run view
  with progress, the wait reason and a Stop button.

The "Into one" merge can no longer be confirmed twice while its call is
in flight. fake_dragonxd gains FAKE_SCAN_SECS, FAKE_MERGE_SERIAL and
FAKE_MERGE_FAIL.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

res/lang/es.json

@@ -1183,6 +1183,22 @@
     "merge_max_inputs": "Máximo de entradas por lote",
     "merge_no_spendable": "Aún no hay entradas disponibles para consolidar.",
     "merge_progress": "Consolidando… esto puede tardar varios minutos. Puedes cerrar esta ventana.",
+    "merge_run_aborted_toast": "La conexión con el nodo se reinició, así que la consolidación se detuvo. Ejecútala de nuevo para continuar.",
+    "merge_run_busy": "Hay una consolidación en curso. Espera a que termine o detenla primero.",
+    "merge_run_chip_fmt": "Consolidando %d/%d",
+    "merge_run_err_timeout": "El nodo no respondió a tiempo; puede que el lote siga en cola.",
+    "merge_run_halted_fmt": "Consolidación detenida tras fallos repetidos: %s",
+    "merge_run_migration_pending": "Termina o cancela la migración de la semilla antes de consolidar.",
+    "merge_run_progress_fmt": "Consolidando… lote %d de unos %d, %d notas fusionadas hasta ahora. Puedes cerrar esta ventana; seguirá en segundo plano.",
+    "merge_run_start_failed": "No se pudo iniciar la consolidación: el nodo no está conectado.",
+    "merge_run_status_not_run": "%s: sin consolidar (%d notas)",
+    "merge_run_status_waiting": "%s: en espera (%d notas)",
+    "merge_run_stop": "Detener",
+    "merge_run_stopped_toast": "Consolidación detenida. Ejecútala de nuevo para fusionar el resto.",
+    "merge_run_stopping": "Deteniendo tras los lotes ya enviados…",
+    "merge_run_wait_batch": "Espaciando los lotes para que el nodo siga respondiendo…",
+    "merge_run_wait_send": "En pausa hasta que se complete tu transacción pendiente.",
+    "merge_run_wait_sync": "En pausa: el nodo aún se está sincronizando.",
     "merge_scope_failed_fmt": "No se pudieron leer tus entradas: %s",
     "merge_scope_fmt": "%d entradas transparentes + %d blindadas  ·  ~%s DRGX disponibles",
     "merge_scope_loading": "Comprobando tus entradas…",