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/zh.json

@@ -1183,6 +1183,22 @@
     "merge_max_inputs": "每批最大输入数",
     "merge_no_spendable": "暂无可合并的可用输入。",
     "merge_progress": "正在合并…这可能需要几分钟。您可以关闭此窗口。",
+    "merge_run_aborted_toast": "节点连接已重置，合并已停止。再次运行以继续。",
+    "merge_run_busy": "正在进行合并。请等待其完成，或先将其停止。",
+    "merge_run_chip_fmt": "合并中 %d/%d",
+    "merge_run_err_timeout": "节点未及时响应；该批次可能仍在队列中。",
+    "merge_run_halted_fmt": "多次失败后合并已停止：%s",
+    "merge_run_migration_pending": "请先完成或取消助记词迁移，再进行合并。",
+    "merge_run_progress_fmt": "正在合并… 第 %d 批（共约 %d 批），已合并 %d 张票据。可以关闭此窗口，合并会在后台继续。",
+    "merge_run_start_failed": "无法开始合并——节点未连接。",
+    "merge_run_status_not_run": "%s——未合并（%d 张票据）",
+    "merge_run_status_waiting": "%s——等待中（%d 张票据）",
+    "merge_run_stop": "停止",
+    "merge_run_stopped_toast": "合并已停止。再次运行以合并其余部分。",
+    "merge_run_stopping": "已发送的批次完成后停止…",
+    "merge_run_wait_batch": "正在间隔各批次，以保持节点响应…",
+    "merge_run_wait_send": "已暂停，等待您的待处理交易完成。",
+    "merge_run_wait_sync": "已暂停：节点仍在同步。",
     "merge_scope_failed_fmt": "无法读取您的输入：%s",
     "merge_scope_fmt": "%d 笔透明输入 + %d 笔屏蔽输入 ・ 约 %s DRGX 可用",
     "merge_scope_loading": "正在检查您的输入…",