ui : Hugging Face Hub data layer (#27947)

* ui : Hugging Face Hub data layer

Add HuggingFaceService and its constants/enums/types: GGUF repo search, file
tree and model detail fetching, quant/sidecar filename analysis, shard-set
collapsing and the llama.app catalog feed, plus an orgOf() helper on the model
name utils.

Assisted-by: pi:GLM-5.3-Flash

* ui : strip provider tilde prefix from hub avatar urls

Assisted-by: pi:llama.cpp/DeepSeek-V4.1-Flash

* ui : trim redundant comments in the HF data layer service

Per review: drop JSDoc that restates the method name and inline comments
that restate the code; keep only comments carrying non-obvious context.

Assisted-by: pi:zai-org/GLM-5.3-Flash

* ui : harden the HF data layer error typing, cover the helpers in tests

Carries the HTTP status on retryable fetch errors instead of matching the
message text. Marks expand-dependent catalog fields optional and documents
the data/models index pairing. Adds table tests for the pure helpers.

Assisted-by: pi:zai-org/GLM-5.3-Flash