fix: Prevent immediate polling on recoverable error

[jsonbailey]

Note

Implements controlled backoff for recoverable HTTP errors and simplifies loop control.

• Replace self._event with self._interrupt_event and clear it at sync start
• After recoverable error (INTERRUPTED), wait poll_interval on self._interrupt_event before retrying
• Use self._interrupt_event.wait(poll_interval) for the regular poll cadence and to break on stop()
• stop() now sets self._interrupt_event to interrupt any pending waits

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