Some TTS providers (e.g. Inworld) return verbatim tokens where spaces and
punctuation are already embedded in the token text. When downstream consumers
join these tokens with an extra space they produce "hello , world" instead of
"hello, world".
Add an opt-in `includes_inter_frame_spaces: bool = False` parameter to
`add_word_timestamps` / `_add_word_timestamps`. The flag is threaded through
`_WordTimestampEntry` and stamped onto every emitted `TTSTextFrame`.
Defaults to `False` — no behaviour change for existing services.
`InworldTTSService` passes `includes_inter_frame_spaces=True` and stops
pre-processing tokens in `_calculate_word_times`, returning them verbatim.
Tests added to `test_tts_frame_ordering.py` covering both HTTP and WebSocket
delivery paths: verbatim text preservation, PTS ordering, text-before-audio
ordering, and the Inworld punctuation-token scenario.
Made-with: Cursor
Route LLMFullResponseEndFrame through the serialization queue instead
of pushing it directly downstream when push_text_frames is enabled.
This ensures the frame is emitted only after the audio context is
fully drained, preserving correct ordering relative to TTSTextFrames.
Previously, the final sentence TTSTextFrame would arrive at the
LLMAssistantAggregator after LLMFullResponseEndFrame, causing it to
be dropped from the conversation context (especially with RTVI text
input where no subsequent interruption would flush the orphaned text).
