Docs update mcp models

[thesteganos]

docs: improve documentation for models and MCP servers

Updated README.md to better direct users to the detailed documentation.

Enhanced models.mdx with instructions and examples for configuring Google Gemini 2.5-flash.

Improved mcp-servers.mdx by clarifying the placement of opencode.json and ensuring comprehensive examples for local and remote

• Added a comprehensive opencode.json example to mcp-servers.mdx, showcasing configuration for both local and remote MCP servers.
• Added a new section to mcp-servers.mdx detailing how to configure MetaMCP, including a specific opencode.json example and explanation of necessary environment variables. MetaMCP can suggest other MPC servers to actual application.
• Restructured mcp-servers.mdx slightly for better flow and clarity between generic examples and the specific MetaMCP example.