Use huggingface_hub_rust for MoE share uploads

[i386]

Summary

mesh-llm moe share now opens dataset contribution PRs through huggingface_hub_rust instead of building a raw NDJSON commit request by hand.

This was extracted from #330 so the Hugging Face upload-path refactor can land independently of the broader MoE expert component sharing work.

What changed

• replace the manual reqwest NDJSON commit flow in mesh-llm moe share with hf_hub::upload_folder
• stage the ranking bundle into a temporary directory and upload that directory as a PR
• show upload phase and byte/file progress while the Hugging Face upload is running
• validate dataset_repo as owner/name before building the dataset client
• keep the existing duplicate-prefix checks and friendly missing-token error path

CLI

Example command:

mesh-llm moe share "allenai/OLMoE-1B-7B-0924-Instruct-GGUF:Q4_K_M"

Representative output still looks like:

📤 MoE ranking share
⬆️ Opening contribution PR...
   ⏫ Uploading files ...
✅ Opened MoE dataset contribution
   commit: <oid>
   url: <commit-url>
   pr: <pr-url>

Validation

• cargo fmt --all -- --check
• cargo check -p mesh-llm
• cargo test -p mesh-llm parse_dataset_repo_requires_owner_and_name
• cargo test -p mesh-llm classify_share_prefix_distinguishes_new_existing_and_partial
• cargo test -p mesh-llm format_upload_bytes_uses_human_units