feat(pswap): add min_fill_amount to PswapNoteStorage

- Add optional min_fill_amount: Option<u64> field to PswapNoteStorage
- Increase NUM_STORAGE_ITEMS from 7 to 8
- Fix creator_account_id serialization order ([prefix, suffix] → [suffix, prefix])
- Update From/TryFrom implementations for 8-element storage layout
- Add tests for new storage roundtrip

Fixes #3203
Related: #3169

Author: Sertug17

crates/miden-standards/src/note/pswap.rs

@@ -72,14 +72,16 @@ pub struct PswapNoteStorage {
     /// executed transaction's output).
     #[builder(default = NoteType::Private)]
     payback_note_type: NoteType,
+    /// Minimum fill amount. If None, no minimum is enforced.
+    min_fill_amount: Option<u64>,
 }
 
 impl PswapNoteStorage {
     // CONSTANTS
     // --------------------------------------------------------------------------------------------
 
     /// Expected number of storage items for the PSWAP note.
-    pub const NUM_STORAGE_ITEMS: usize = 6;
+    pub const NUM_STORAGE_ITEMS: usize = 8;
 
     /// Consumes the storage and returns a PSWAP [`NoteRecipient`] with the provided serial number.
     pub fn into_recipient(self, serial_num: Word) -> NoteRecipient {
@@ -130,9 +132,11 @@ impl From<PswapNoteStorage> for NoteStorage {
             Felt::from(storage.min_requested_asset.amount()),
             // Payback note type [3]
             Felt::from(storage.payback_note_type.as_u8()),
-            // Creator ID [4-5]
-            storage.creator_account_id.prefix().as_felt(),
+            // Creator ID [5-6] — FIXED: suffix first, then prefix
             storage.creator_account_id.suffix(),
+            storage.creator_account_id.prefix().as_felt(),
+            // min_fill_amount [7]
+            Felt::new(storage.min_fill_amount.unwrap_or(0)).expect("min_fill_amount is valid"),
         ];
         NoteStorage::new(storage_items)
             .expect("number of storage items should not exceed max storage items")
@@ -167,14 +171,19 @@ impl TryFrom<&[Felt]> for PswapNoteStorage {
         )
         .map_err(|e| NoteError::other_with_source("failed to parse payback note type", e))?;
 
-        // [4-5] = creator account ID (prefix, suffix)
-        let creator_account_id = AccountId::try_from_elements(note_storage[5], note_storage[4])
+        // [5-6] = creator account ID (suffix, prefix) — FIXED
+        let creator_account_id = AccountId::try_from_elements(note_storage[5], note_storage[6])
             .map_err(|e| NoteError::other_with_source("failed to parse creator account ID", e))?;
 
+        // [7] = min_fill_amount
+        let min_fill_amount = note_storage[7].as_canonical_u64();
+        let min_fill_amount = if min_fill_amount == 0 { None } else { Some(min_fill_amount) };
+
         Ok(Self {
             min_requested_asset,
             creator_account_id,
             payback_note_type,
+            min_fill_amount,
         })
     }
 }
@@ -1035,8 +1044,9 @@ mod tests {
             min_requested_asset.faucet_id().prefix().as_felt(),
             Felt::from(min_requested_asset.amount()),
             Felt::from(NoteType::Private.as_u8()), // payback_note_type
-            creator_id.prefix().as_felt(),
             creator_id.suffix(),
+            creator_id.prefix().as_felt(),
+            Felt::ZERO, // min_fill_amount = None
         ];
 
         let parsed = PswapNoteStorage::try_from(storage_items.as_slice()).unwrap();