ui : extract discover pipeline tags, memory and serve-command constants
Move remaining magic strings in the discover UI into $lib/constants:
- HF modalities: HF_MODALITY_PIPELINE_TAGS (vision/audio/video pipeline_tag
groups) and HF_MMPROJ_FILENAME_TOKEN; reuse MODEL_ID.ORG_SEPARATOR for the
org split.
- Bit-depth row: OTHER_BIT_DEPTH_LABEL, BIT_DEPTH_LABEL_SUFFIX and the
existing GIGABYTE_LABEL / OTHER_BIT_DEPTH instead of 'Other', '-bit', 'GB'.
- Serve command preview: a SERVE_COMMAND constants object (llama/serve/-hf/
-hfd/--spec-type) plus MODEL_ID.QUANTIZATION_SEPARATOR for the ':' join.
Assisted-by: llama-ui:Qwen3.8-Flash-Next