Simplify subscription quote fetching by removing try_join_all

Replace batch query execution with inline sequential processing for melt and
mint quote lookups. This reduces code complexity by handling each quote type
immediately within the match statement instead of collecting futures and
joining them at the end.

crates/cdk/src/mint/subscription.rs

@@ -57,75 +57,46 @@ impl MintPubSubSpec {
     ) -> Result<Vec<MintEvent<QuoteId>>, String> {
         let mut to_return = vec![];
         let mut public_keys: Vec<PublicKey> = Vec::new();
-        let mut melt_queries = Vec::new();
-        let mut mint_queries = Vec::new();
 
         for idx in request.iter() {
             match idx {
                 NotificationId::ProofState(pk) => public_keys.push(*pk),
-                NotificationId::MeltQuoteBolt11(uuid) => {
-                    melt_queries.push(self.db.get_melt_quote(uuid))
+                NotificationId::MeltQuoteBolt11(uuid) | NotificationId::MeltQuoteBolt12(uuid) => {
+                    if let Some(melt_quote) = self
+                        .db
+                        .get_melt_quote(uuid)
+                        .await
+                        .map_err(|e| e.to_string())?
+                    {
+                        let melt_quote: MeltQuoteBolt11Response<_> = melt_quote.into();
+                        to_return.push(melt_quote.into());
+                    }
                 }
-                NotificationId::MintQuoteBolt11(uuid) => {
-                    mint_queries.push(self.get_mint_quote(uuid))
-                }
-                NotificationId::MintQuoteBolt12(uuid) => {
-                    mint_queries.push(self.get_mint_quote(uuid))
-                }
-                NotificationId::MeltQuoteBolt12(uuid) => {
-                    melt_queries.push(self.db.get_melt_quote(uuid))
+                NotificationId::MintQuoteBolt11(uuid) | NotificationId::MintQuoteBolt12(uuid) => {
+                    if let Some(mint_quote) =
+                        self.get_mint_quote(uuid).await.map_err(|e| e.to_string())?
+                    {
+                        let mint_quote = match mint_quote.payment_method.as_str() {
+                            "bolt11" => {
+                                let response: MintQuoteBolt11Response<QuoteId> = mint_quote.into();
+                                response.into()
+                            }
+                            "bolt12" => match mint_quote.try_into() {
+                                Ok(response) => {
+                                    let response: MintQuoteBolt12Response<QuoteId> = response;
+                                    response.into()
+                                }
+                                Err(_) => continue,
+                            },
+                            _ => continue,
+                        };
+
+                        to_return.push(mint_quote);
+                    }
                 }
             }
         }
 
-        if !melt_queries.is_empty() {
-            to_return.extend(
-                futures::future::try_join_all(melt_queries)
-                    .await
-                    .map(|quotes| {
-                        quotes
-                            .into_iter()
-                            .filter_map(|quote| quote.map(|x| x.into()))
-                            .map(|x: MeltQuoteBolt11Response<QuoteId>| x.into())
-                            .collect::<Vec<_>>()
-                    })
-                    .map_err(|e| e.to_string())?,
-            );
-        }
-
-        if !mint_queries.is_empty() {
-            to_return.extend(
-                futures::future::try_join_all(mint_queries)
-                    .await
-                    .map(|quotes| {
-                        quotes
-                            .into_iter()
-                            .filter_map(|quote| {
-                                quote.and_then(|mint_quotes| {
-                                    match mint_quotes.payment_method.as_str() {
-                                        "bolt11" => {
-                                            let response: MintQuoteBolt11Response<QuoteId> =
-                                                mint_quotes.into();
-                                            Some(response.into())
-                                        }
-                                        "bolt12" => match mint_quotes.try_into() {
-                                            Ok(response) => {
-                                                let response: MintQuoteBolt12Response<QuoteId> =
-                                                    response;
-                                                Some(response.into())
-                                            }
-                                            Err(_) => None,
-                                        },
-                                        _ => None,
-                                    }
-                                })
-                            })
-                            .collect::<Vec<_>>()
-                    })
-                    .map_err(|e| e.to_string())?,
-            );
-        }
-
         if !public_keys.is_empty() {
             to_return.extend(
                 self.db