arcint 1.2.0 — voice and vision

This is not the current release. The current one is here, with its changes in CHANGELOG.md.

Voice and vision (docs/milestone-1.2.0.md, the units' contract
docs/speech-service.md): three on-demand units on the Arc Pro B60, each
with Conflicts= against the card's language, image and other speech units.

• Vision input, arcint-vlm on :8083: Qwen2.5-VL-7B-Instruct (Q4_K_M,
  Q8_0 projector) through llama.cpp's libmtmd, now linked into arcint.
  /v1/chat/completions takes OpenAI image_url parts as
  data:image/...;base64 URIs (a file path or a remote URL is 400), at most
  8 images of at most 16.8 M pixels a request; an image prompt over the lane
  is the usual 400 context_length_exceeded. /props reports the
  projector's vision and audio halves.
• Text to speech with voice cloning, arcint-tts on :8084: Qwen3-TTS
  12Hz 1.7B Base, German. --tts --tts-profiles DIR; /v1/audio/speech
  takes a voice name from the server's enrolled profiles
  (/v1/audio/voices) and refuses any reference-audio field: a voice is
  enrolled on the host with tools/tts_enrol.py (shipped in
  /usr/share/arcint/), never through the API. --tts-gen-device cpu, the
  unit's placement (operator's decision): the backbone on the card, the
  projector's speaker encoder, code predictor and acoustic decoder on the
  CPU. The production projector is Q8_0 with the code head and embedding at
  f16. A TTS unit refuses chat with 400.
• Speech to text, arcint-stt on :8091, the new package arcint-stt:
  whisper.cpp v1.9.5's server (arcint-whisper) built against the ggml
  installed from arcint's patched tree, Whisper large-v3-turbo,
  /v1/audio/transcriptions; its patch adds /props (the model, the
  decoding defaults, the GPU device in use, the build) and stops serving
  upstream's /load.
• 0062, libmtmd's Qwen3-TTS acoustic decoder decodes the frames it is
  given instead of a padded 72-frame window (tools/mtmd only).
• The arcint package ships the arcint-vlm and arcint-tts unit
  templates beside arcint.service.

Runtime: llama.cpp 3e4dfa8 with contrib/llama.cpp/patches (59
patches, 0001-0062 without 0031, 0055 and 0061), compiled in, with
libmtmd; dependencies as in 0.8.0. arcint-stt: whisper.cpp d1be6fde
on the same tree. arcint-imggen is unchanged (1.1.1).

Release check (measured-here, 2026-10-19, the pre-tag packages;
milestone §9.11): the release gate tests/acceptance/ab.py against 1.1.1's
binary, alternated: the coder 51.10 / 47.60 / 44.10 t/s and 725.20 at 41k
(1.1.1 the same decode, 725.45), the agent 709.35 / 498.90 t/s at 55k /
138k (equal to 1.1.1), every answer right and the same bytes in every run of
both binaries on both cards; the acceptance task 9/10 (coder) and 10/10
(agent). No KL arm: the llama.cpp trees differ only in tools/mtmd. VLM
gate 9/9 (floor 1.0, whole-word matching; its red, wrong expectations, 0/9);
TTS real-time factor 1.1167 (floor 1.0) and round-trip WER 0.0264 (floor
0.10, worst sentence 0.333, floor 0.5) on 46 Tatoeba sentences; STT WER
0.0547 on 12 FLEURS de clips (floor 0.08, equal to the CPU run). The image
input fixes against the pre-fix binary as their red: a file path in
image_url was opened, a streamed bad image ended the process; on 1.2.0
both are 400 / an error event, and the process serves on.
Open after the release: the voice-similarity floor (C5) needs the household
speakers' own recordings, two each; naturalness is judged by ear.

Packages (Debian trixie, amd64): arcint 1.2.0-1 and the new arcint-stt 1.2.0-1; arcint-imggen stays 1.1.1-1.