refactor: remove caching of MCP metadata in MultiServerMCPClient

[imranq2]

This PR removes the caching mechanism for MCP (Model Configuration Protocol) metadata, transitioning to a strategy where tool metadata is fetched fresh from the MCP server on every request. The refactoring removes the McpToolsMetadataExpiringCache class entirely and updates all dependent components to eliminate cache-related logic.

Deleted the entire mcp_tools_expiring_cache.py file containing the caching implementation
Updated MultiServerMCPClientWithCaching to always load fresh metadata instead of using cached data
Removed cache dependencies from MCPToolProvider and the dependency injection container
Simplified the get_tools method to directly load and convert tools without cache management

[Copilot]

Pull request overview

This PR removes the caching mechanism for MCP (Model Configuration Protocol) metadata, transitioning to a strategy where tool metadata is fetched fresh from the MCP server on every request. The refactoring removes the McpToolsMetadataExpiringCache class entirely and updates all dependent components to eliminate cache-related logic.

• Deleted the entire mcp_tools_expiring_cache.py file containing the caching implementation
• Updated MultiServerMCPClientWithCaching to always load fresh metadata instead of using cached data
• Removed cache dependencies from MCPToolProvider and the dependency injection container
• Simplified the get_tools method to directly load and convert tools without cache management

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
language_model_gateway/gateway/utilities/cache/mcp_tools_expiring_cache.py	Complete removal of the MCP tools metadata caching implementation
language_model_gateway/gateway/tools/mcp_tool_provider.py	Removed cache parameter from constructor and updated initialization logic
language_model_gateway/gateway/langchain_overrides/multiserver_mcp_client_with_caching.py	Refactored to always fetch fresh metadata; removed all caching logic from get_tools and related methods
language_model_gateway/container/container_factory.py	Removed singleton registration for McpToolsMetadataExpiringCache and removed cache injection into MCPToolProvider

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[Copilot]

The removal of the default value (= None) from the session parameter changes the method signature. While this doesn't break existing code (since all current callers explicitly pass session=None), it does change the API by requiring callers to explicitly provide a value for session instead of being able to omit it. Consider whether this is intentional or if the default value should be preserved for backward compatibility.

Suggested change

	session: ClientSession | None,
	session: ClientSession | None = None,