[FIX] NUT-15 mpp amount in millisats (#703)

* fix lndrest

* fix clnrest

* fix clnrest and lndrest

* lnd grpc fix

* wallet

* convert amount to millisats in CLI pay invoice

* fix tests

* format

* fix kw arg in regtest test

* fix payment quote validation check

* clean comment

* avoid overwriting variable

* deprecated response with amount

---------

Co-authored-by: callebtc <93376500+callebtc@users.noreply.github.com>

cashu/wallet/v1_api.py

@@ -434,16 +434,17 @@ class LedgerAPI(LedgerAPIDeprecated, SupportsAuth):
     @async_set_httpx_client
     @async_ensure_mint_loaded
     async def melt_quote(
-        self, payment_request: str, unit: Unit, amount: Optional[int] = None
+        self, payment_request: str, unit: Unit, amount_msat: Optional[int] = None
     ) -> PostMeltQuoteResponse:
         """Checks whether the Lightning payment is internal."""
         invoice_obj = bolt11.decode(payment_request)
         assert invoice_obj.amount_msat, "invoice must have amount"
+
         # add mpp amount for partial melts
         melt_options = None
-        if amount:
+        if amount_msat:
             melt_options = PostMeltRequestOptions(
-                mpp=PostMeltRequestOptionMpp(amount=amount)
+                mpp=PostMeltRequestOptionMpp(amount=amount_msat)
             )
 
         payload = PostMeltQuoteRequest(
@@ -462,9 +463,12 @@ class LedgerAPI(LedgerAPIDeprecated, SupportsAuth):
                 payment_request
             )
             quote_id = f"deprecated_{uuid.uuid4()}"
+            amount_sat = (
+                amount_msat // 1000 if amount_msat else invoice_obj.amount_msat // 1000
+            )
             return PostMeltQuoteResponse(
                 quote=quote_id,
-                amount=amount or invoice_obj.amount_msat // 1000,
+                amount=amount_sat,
                 fee_reserve=ret.fee or 0,
                 paid=False,
                 state=MeltQuoteState.unpaid.value,