feat(beta): add DateTimeHelperTool toolset

[rektdeckard]

Adds a DateTimeHelperTool toolset which the agent can use to access the current time, adjusted for timezone either statically or provided as an argument by the LLM at call time. It can also compute absolute offsets ("in 3 hours"), and be used effectively by LLMs when a relative date or offset is required (e.g. "next Tuesday at 4pm").

If timezone is not provided, defaults to UTC.

class Assistant(Agent):
    def __init__(self):
        super().__init__(
            instructions="""You are a helpful voice AI assistant.""",
            tools=[
                DateTimeHelperTool(tz="America/Denver"),
            ],
        )

[devin-ai-integration]

✅ Devin Review: No Issues Found

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