Reorganize imports in client.py

- Move json import to top-level imports
- Add asyncio and contextlib.suppress imports for future use
- Remove inline json import from query method

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/claude_code_sdk/client.py

@@ -1,7 +1,10 @@
 """Claude SDK Client for interacting with Claude Code."""
 
+import asyncio
+import json
 import os
 from collections.abc import AsyncIterable, AsyncIterator
+from contextlib import suppress
 from typing import Any
 
 from ._errors import CLIConnectionError
@@ -164,8 +167,6 @@ class ClaudeSDKClient:
         if not self._query or not self._transport:
             raise CLIConnectionError("Not connected. Call connect() first.")
 
-        import json
-
         # Handle string prompts
         if isinstance(prompt, str):
             message = {