Allow actions to request user input for human-in-the-loop interactions

Closes #2484 (closed)

User Input Support for Workflows

• Action State Tracking: Added user_input_requests to the MongoDB ActionDocument and API models so workflows can track when they are waiting for human input.
• Workflow Pausing: Centralized a new request_user_input_activity within the core actions manager that any Temporal workflow can use to register that it needs input.
• Schema Generation: Overhauled schema extraction to dynamically inspect @workflow.signal definitions, automatically generating JSON Schemas for the expected inputs.
• Input Submission API: Exposed a new /{action_instance_id}/user-input HTTP POST endpoint that takes a payload and relays it as a signal to the Temporal workflow.

UI is still wip, but rough idea of how it works:

Example workflow:

Only step 2 is NOMAD specific code, everything else is standard Temporal features.

class UserInputExampleWorkflow:
    def __init__(self) -> None:
        self._user_input: UserInputData | None = None

    @workflow.signal
    def provide_input(self, data: UserInputData) -> None:
        self._user_input = data

    @workflow.run
    async def run(self, data: UserInputExampleWorkflowInput) -> dict:
        # 1. Generate a random number between the specified bounds
        random_number = await workflow.execute_activity(
            generate_random_number_activity,
            args=[data.lower_bound, data.upper_bound],
            start_to_close_timeout=timedelta(seconds=10),
        )

        markdown_content = f"""### Random Number Generated

        We have successfully generated a random number for you!

        **Details:**
        - Generated value: `{random_number}`
        - Requested range: `[{data.lower_bound}, {data.upper_bound}]`

        Please review this number and **approve** or **reject** it below.
        """
        # 2. Ask the backend to log that we are waiting for user input
        await request_user_input(
            action_instance_id=workflow.info().workflow_id,
            user_id=data.user_id,
            signal_fn_name='provide_input',
            title='Review Required',
            description=f'Please approve or reject the randomly generated number: {random_number}.',
            content=markdown_content,
        )

        # 3. Suspend workflow execution until the signal is received
        await workflow.wait_condition(lambda: self._user_input is not None)

        # 4. Resume and return the final decision regarding the random number
        decision_str = "approved" if self._user_input.decision.lower() == "approve" else "rejected"
        return {
            'status': 'success',
            'message': f"user {decision_str} {random_number}",
            'user_notes': self._user_input.notes,
        }