feat: add manual USDT account rebalance

docs/binance-orderbook-trade-development.md

@@ -153,6 +153,12 @@ Every Binance UI automation change must report the evidence used: live DOM or st
 
 Do not auto-confirm destructive Binance dialogs. The script may open Binance's native cancel confirmation, but final confirmation remains manual.
 
+USDT account rebalancing is a manual action, not an automatic post-close side effect. The inline `再平衡` action becomes available only after the account-order widget has continuously reported zero positions and zero open orders for three seconds, and a fresh all-symbol futures-position response also confirms that every position is flat. Starting any script trade or cancel task invalidates that eligibility immediately.
+
+The rebalance path is pinned to the current Binance page bundle contract instead of automating the native transfer dialog. It reads Spot and Funding available USDT from `/bapi/asset/v2/private/asset-service/wallet/balance`, reads the U-M Futures transferable amount from `/bapi/futures/v1/private/future/user-data/getMaxWithdrawAmount`, and submits at most two sequential transfers through `/bapi/asset/v1/private/asset-service/wallet/transfer` with `{ asset, amount, kindType }`. The private transfer BAPI uses the page bundle's `MAIN`, `CARD`, and `FUTURE` account codes; do not substitute the public SAPI names `FUNDING` or `UMFUTURE`. It does not save an API key and does not fall back to DOM clicking if this private BAPI contract changes.
+
+The user must approve one native confirmation that shows the current balances, 5:4:1 targets, and exact transfer list. After confirmation, the script rechecks all positions, all open orders, and the exact three-account balance snapshot before every transfer. Each successful response must then be reflected by a fresh balance read before the next transfer starts. An intervening position, order, or balance change stops the task; a partial completion is reported explicitly and is never retried or rolled back automatically.
+
 Ladder replacement must stay scoped and direction-aware. Automatic replacement may cancel only visible basic open-order rows for the current symbol and the same plan direction (`开多`, `开空`, `平多`, or `平空`). It must not use current-symbol cancel-all for ladder replacement, must not touch conditional/protection orders, and must retry the ladder plan only after the replacement path is validated by current DOM rows.
 
 User-facing failures must preserve the observed reason instead of collapsing multiple states into one generic message. In particular, an unread openable quantity, a confirmed zero available balance, and a Binance-calculated openable quantity of zero are separate outcomes. Use the panel term `价格精度` consistently instead of exposing the internal `缩放值` name. Cancellation feedback should describe the user-visible action and result, not implementation details such as row-by-row processing, observer roots, context loss, or temporary chart-state manipulation. Combined `A or B` failures are allowed only when the code cannot distinguish the causes; when each branch is already known, report that branch directly.