feat(wasm-utxo): add version info to PSBT proprietary fields

Add set_version_info method to BitGoPsbt that embeds the wasm-utxo
version and git hash into the PSBT's proprietary fields. This allows
easy identification of which library version processed the PSBT.

Issue: BTC-2992

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

packages/wasm-utxo/src/fixed_script_wallet/bitgo_psbt/mod.rs

@@ -1178,6 +1178,17 @@ impl BitGoPsbt {
         }
     }
 
+    /// Set version information in the PSBT's proprietary fields
+    ///
+    /// This embeds the wasm-utxo version and git hash into the PSBT's global
+    /// proprietary fields, allowing identification of which library version
+    /// processed the PSBT.
+    pub fn set_version_info(&mut self) {
+        let version_info = WasmUtxoVersionInfo::from_build_info();
+        let (key, value) = version_info.to_proprietary_kv();
+        self.psbt_mut().proprietary.insert(key, value);
+    }
+
     pub fn finalize_input<C: secp256k1::Verification>(
         &mut self,
         secp: &secp256k1::Secp256k1<C>,
@@ -4426,4 +4437,33 @@ mod tests {
             .expect("decode extracted tx");
         assert_eq!(decoded.compute_txid(), extracted_tx.compute_txid());
     }
+
+    #[test]
+    fn test_set_version_info() {
+        use crate::fixed_script_wallet::test_utils::get_test_wallet_keys;
+        use miniscript::bitcoin::psbt::raw::ProprietaryKey;
+
+        let wallet_keys =
+            crate::fixed_script_wallet::RootWalletKeys::new(get_test_wallet_keys("doge_1e19"));
+
+        let mut psbt = BitGoPsbt::new(Network::Bitcoin, &wallet_keys, Some(2), Some(0));
+
+        // Set version info
+        psbt.set_version_info();
+
+        // Verify it was set in the proprietary fields
+        let version_key = ProprietaryKey {
+            prefix: BITGO.to_vec(),
+            subtype: ProprietaryKeySubtype::WasmUtxoVersion as u8,
+            key: vec![],
+        };
+
+        assert!(psbt.psbt().proprietary.contains_key(&version_key));
+
+        // Verify the value is correctly formatted
+        let value = psbt.psbt().proprietary.get(&version_key).unwrap();
+        let version_info = WasmUtxoVersionInfo::from_bytes(value).unwrap();
+        assert!(!version_info.version.is_empty());
+        assert!(!version_info.git_hash.is_empty());
+    }
 }