Adds InceptionLLMService, an OpenAI-compatible service for Inception's
Mercury-2 diffusion-based reasoning model. Supports reasoning_effort
(instant/low/medium/high) and realtime mode for reduced TTFT.
Adds tests for AggregatedFrameSequencer, WordCompletionTracker, and
word_timestamp_utils (including CJK language scenarios). Updates existing
Cartesia TTS and TTS frame ordering tests to cover the new behaviours.
TTSTextFrame entries were losing their original text structure when word
timestamps were enabled. AggregatedTextFrame now carries a raw_text field with
the original LLM-produced text (including pattern delimiters such as
<card>...</card>). The assistant context receives properly-tagged content
rather than the cleaned words returned by the TTS provider. Also handles words
that straddle two sentence boundaries by splitting and attributing each part
to its correct source frame.
SSML markup (e.g. <spell>, <emotion>, <break>) was leaking into word entries
returned by the Cartesia word-timestamps API. Tags are now stripped before
processing so word-to-text attribution remains accurate when SSML is present
in the TTS input.
Frames sharing the same presentation timestamp were being reordered by the
priority queue. Adds a monotonic counter as a tiebreaker so frames with equal
PTS are always emitted in insertion order, preventing subtle audio/text
sequencing bugs.
Skipped frames (e.g. code blocks filtered via skip_aggregator_types) were
emitted to the assistant context immediately instead of waiting for preceding
spoken frames to finish. Introduces AggregatedFrameSequencer to hold each
frame's slot and flush only after all earlier spoken sentences are complete,
keeping context ordering correct.
The keepalive could fire for a new turn's context before that context's
voice_settings context-init was sent, making the keepalive the context's
first message (no voice_settings) and causing ElevenLabs to reject the
later init with a 1008 policy violation. The keepalive now only targets a
context once its context-init has been sent (tracked in _context_init_sent).
