Allow grouping multiple tools under a single confirmation strategy

[sjrl]

It would be nice to support assigning one confirmation strategy to multiple tools to avoid duplicate configuration.

For example, we could allow confirmation_strategies to accept multiple tool names as a single key:

confirmation_strategies = {
    ("tool1", "tool2", "tool3"): BlockingConfirmationStrategy()
}

instead of currently needing

confirmation_strategies = {
    "tool1": BlockingConfirmationStrategy(),
    "tool2": BlockingConfirmationStrategy(),
    "tool3": BlockingConfirmationStrategy()
}

This would become especially verbose when you have lots of tools accessible to the Agent