Feature Request: Support overriding the default embedding model via CLI arguments

[AikawaKazuki]

First of all, thank you for developing cocoindex-code-mcp-server! It has been incredibly useful in my daily development workflow and helps me navigate codebases efficiently.

I would like to request a feature to override the default embedding model via a command-line argument.
Add an --default-embedding-model argument to specify the model ID directly.

Example Usage:

  python -m cocoindex_code_mcp_server.main_mcp_server --rescan --port 3033 --default-embedding --default-embedding-model ibm-granite/granite-embedding-278m-multilingual <path_to_code_directory>

Context:
Currently, the server seems to function with either the language-aware "Smart Embedding" (switching between GraphCodeBERT/UniXcoder) or the generic defaults via the --default-embedding flag.

However, I would like to use a specific embedding model of my choice (e.g., a specific Hugging Face model ID) for default-embedding-model to better suit my needs, such as using a multilingual model or a lighter/heavier model depending on the environment.

Thank you for considering this request!