style: Format code with ruff and fix linting issues

- Applied ruff formatting to all example files
- Fixed unused variable warning (prefixed with underscore)
- Fixed sys.exit() usage instead of exit()
- All ruff checks now pass

Author: big14way

examples/03_fassets_basic.py

@@ -141,7 +141,7 @@ async def demonstrate_minting_workflow(fassets: FAssets) -> None:
         )
         minted_amount = await fassets.execute_minting(
             FAssetType.FXRP,
-            int(reservation_id.get('reservation_id', 0)),
+            int(reservation_id.get("reservation_id", 0)),
             payment_reference,
             executor,
         )
@@ -169,7 +169,7 @@ async def perform_redemption_operations(fassets: FAssets) -> None:
         print(f"Redemption Request ID: {redemption_id}")
 
         # Get redemption request details
-        request_id = int(redemption_id.get('request_id', 0))
+        request_id = int(redemption_id.get("request_id", 0))
         if request_id > 0:
             redemption_details: dict[str, Any] = await fassets.get_redemption_request(
                 FAssetType.FXRP, request_id

examples/06_turnkey_wallet_integration.py

@@ -330,7 +330,7 @@ async def main() -> None:
         wallet = await setup_turnkey_wallet()
 
         # 2. Create demo wallet
-        wallet_id, wallet_address = await create_demo_wallet(wallet)
+        wallet_id, _wallet_address = await create_demo_wallet(wallet)
 
         # 3. Set up TEE security manager
         tee_manager = TEESecurityManager()

examples/07_rag_vector_demo.py

@@ -1,3 +1,4 @@
+import sys
 from pathlib import Path
 
 from qdrant_client import QdrantClient
@@ -43,8 +44,8 @@
         print("❌ GEMINI_API_KEY environment variable not set.")
         print("Please set the GEMINI_API_KEY environment variable to run this demo.")
         print("Example: export GEMINI_API_KEY='your_api_key_here'")
-        exit(1)
-    
+        sys.exit(1)
+
     embedding_model = GeminiEmbedding(
         api_key=agent.gemini_api_key.get_secret_value(),
         model=vector_db.embeddings_model,