feat(amm): let LPs choose the LP-token destination account

Add-liquidity minted a fresh LP account every time, fragmenting a position
across holdings. The New position form now has an LP-destination selector (the
same Input-mode component as the token funding rows): add-liquidity preselects
the wallet's existing LP holding so deposits consolidate, while create-pool has
none and mints a fresh one.

- addLiquidityQuote returns lpDefinitionId (base58) so the form matches holdings
- createPool/addLiquidity submit into the chosen holding, else create-fresh
- e2e: add-liquidity waits for the preselect; create-pool asserts fresh-account

modules/amm/ffi/src/api/liquidity.rs

@@ -307,6 +307,9 @@ pub(super) fn add_liquidity_quote(request: AddLiquidityQuoteRequest) -> Result<V
         "expectedLp": delta_lp.to_string(),
         "minimumLp": minimum_lp.to_string(),
         "price": price.to_string(),
+        // The pool's LP token definition (base58, matching the holdings' definitionId) so
+        // the UI can offer the wallet's existing LP holdings as the mint destination.
+        "lpDefinitionId": pool.liquidity_pool_id.to_string(),
     }))
 }
 

modules/amm/src/amm_module_impl.cpp

@@ -1036,7 +1036,8 @@ LogosMap AmmModuleImpl::addLiquidityQuote(const LogosMap& request) {
     if (!quoteResult.ok)
         return error(quoteResult.error.empty() ? "backend_error" : quoteResult.error);
 
-    // Success: wrap { amountA, amountB, expectedLp, minimumLp, price }.
+    // Success: wrap { amountA, amountB, expectedLp, minimumLp, price, lpDefinitionId }.
+    // (lpDefinitionId is the pool's LP token so the UI can offer existing LP holdings.)
     LogosMap out = quoteResult.value;
     out["status"] = "ok";
     out["error"] = "";