feat(runtime): Add prototype Runloop runtime impl

[ross-rl]

End-user friendly description of the problem this fixes or functionality that this introduces Add Runloop runtime implementation on top of EventStreamRuntime

• [ ] Include this change in the Release Notes. If checked, you must provide an end-user friendly description for your change below

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Give a summary of what the PR does, explaining any non-trivial design decisions This PR adds a Runloop runtime implementation, primarily utilizing EventStreamRuntime and its associated communication mechanisms

This runtime:

• creates a runloop Devbox will use a pre-built openhands sandbox image built against dockerfile.j2
• creates a url / tunnel to the Devbox
• delegates application level interface methods (run_action) to EventStreamRuntime

Also included is a polling based LogBuffer

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Link of any specific issues this addresses