fix(ds4): resolve repository imports to GGUF
Select a concrete DeepSeek V4 Flash GGUF from Hugging Face metadata while honoring quantization preference order. Reject unresolved repository imports instead of emitting an invalid bare URI.
Assisted-by: Codex:gpt-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>