- Added ps_endpointer_timestamp_cb_t callback type for external timestamps
- Added ps_endpointer_set_timestamp_func() to set external timestamp source
- Added ps_endpointer_timestamp() to get current timestamp
- Modified internal timestamp handling to use callback when available
- Maintains full backward compatibility - existing code works unchanged
- Added comprehensive test suite (test_endpointer_timestamp)
- Added example program demonstrating the new functionality
This addresses issue #352 by allowing applications to provide their own
timestamp source (e.g., system time, monotonic clock) to avoid drift
between audio clock and system clock. The implementation maintains the
audio-based timestamp tracking internally for queue management while
using the external source for speech start/end timestamps when provided.
Kevin Lenzo