Feat: add user input tool

[declanjackson]

Add USER_INPUT Tool

Adds a new tool USER_INPUT that enables agents to interactively ask users questions during task execution, supporting text input, multiple choice, and yes/no confirmation prompts.

Key user input changes:

• New USER_INPUT tool with three question types: text, choice, and confirm
• Logger pause/resume functionality to prevent spinner interference during user prompts
• Dynamic system prompt that adapts based on whether the user_input tool is available

Other clean up changes:

• Changed code execution logs from info to debug level for cleaner output

To test, import USER_INPUT_TOOL from stirrup.tools and add to agent tools like so:

agent = Agent(client=client, name="agent", tools=[*DEFAULT_TOOLS, USER_INPUT_TOOL], max_turns=15)

Display example: