remove mint_quote_signature_required as per spec

.env.example

@@ -131,7 +131,3 @@ LIGHTNING_RESERVE_FEE_MIN=2000
 # MINT_GLOBAL_RATE_LIMIT_PER_MINUTE=60
 # Determines the number of transactions (mint, melt, swap) allowed per minute per IP
 # MINT_TRANSACTION_RATE_LIMIT_PER_MINUTE=20
-
-# --------- MINT FEATURES ---------
-# Require NUT-19 signature for mint quotes
-MINT_QUOTE_SIGNATURE_REQUIRED=FALSE

cashu/core/errors.py

@@ -98,7 +98,7 @@ def __init__(self):
         super().__init__(self.detail, code=2001)
 
 class QuoteInvalidWitnessError(CashuError):
-    detail = "Witness on mint request not provided or invalid"
+    detail = "Signature for mint request invalid"
     code = 20008
 
     def __init__(self):

cashu/core/settings.py

@@ -63,7 +63,6 @@ class MintSettings(CashuSettings):
 
     mint_input_fee_ppk: int = Field(default=0)
     mint_disable_melt_on_error: bool = Field(default=False)
-    mint_quote_signature_required: bool = Field(default=False)
 
 
 class MintDeprecationFlags(MintSettings):

cashu/mint/ledger.py

@@ -39,7 +39,6 @@
     NotAllowedError,
     QuoteInvalidWitnessError,
     QuoteNotPaidError,
-    QuoteRequiresPubkeyError,
     TransactionError,
 )
 from ..core.helpers import sum_proofs
@@ -425,9 +424,6 @@ async def mint_quote(self, quote_request: PostMintQuoteRequest) -> MintQuote:
             if balance + quote_request.amount > settings.mint_max_balance:
                 raise NotAllowedError("Mint has reached maximum balance.")
 
-        if settings.mint_quote_signature_required and not quote_request.pubkey:
-            raise QuoteRequiresPubkeyError()
-
         logger.trace(f"requesting invoice for {unit.str(quote_request.amount)}")
         invoice_response: InvoiceResponse = await self.backends[method][
             unit