Remove max thinking tokens (#144)

It's not used anywhere and it can be set through the env parameter

`ClaudeCodeOptions(env={"MAX_THINKING_TOKENS" : 8000})`

examples/streaming_mode.py

@@ -217,7 +217,6 @@ async def example_with_options():
     # Configure options
     options = ClaudeCodeOptions(
         allowed_tools=["Read", "Write"],  # Allow file operations
-        max_thinking_tokens=10000,
         system_prompt="You are a helpful coding assistant.",
         env={
             "ANTHROPIC_MODEL": "claude-3-7-sonnet-20250219",

src/claude_code_sdk/types.py

@@ -271,7 +271,6 @@ class ClaudeCodeOptions:
     """Query options for Claude SDK."""
 
     allowed_tools: list[str] = field(default_factory=list)
-    max_thinking_tokens: int = 8000
     system_prompt: str | None = None
     append_system_prompt: str | None = None
     mcp_servers: dict[str, McpServerConfig] | str | Path = field(default_factory=dict)

tests/test_types.py

@@ -80,7 +80,6 @@ class TestOptions:
         """Test Options with default values."""
         options = ClaudeCodeOptions()
         assert options.allowed_tools == []
-        assert options.max_thinking_tokens == 8000
         assert options.system_prompt is None
         assert options.permission_mode is None
         assert options.continue_conversation is False