Refactor: Introduce useActionHandler pattern and standardize logging

[plvo]

Summary

This PR refactors the MCP plugin actions to use a centralized context pattern and improves logging consistency across the codebase.

Key Changes

Context-based Action Handler Pattern

• Introduced useActionHandler utility that returns a complete ActionHandlerContext
• Eliminates code duplication between callToolAction.ts and readResourceAction.ts
• Centralizes state composition and MCP service retrieval
• Uses spread operator pattern for cleaner function calls

Before:

const composedState = await runtime.composeState(message, ["RECENT_MESSAGES", "MCP"]);
const mcpService = runtime.getService<McpService>(MCP_SERVICE_NAME);
const mcpProvider = mcpService.getProviderData();

After:

const context = await useActionHandler({ actionName: ACTION_NAME, runtime, message, state, options, callback });
const toolSelectionName = await createToolSelectionName({...context});

Standardized Logging with mcpLogger

• Replaced direct logger usage with centralized mcpLogger
• Added consistent [MCP] prefixes and contextual tags ([CALLING], [SELECTED], [HANDLE])
• Improved observability and debugging across MCP operations

Code Organization

• Cleaned up imports using TypeScript's type imports
• Moved utility functions to appropriate modules
• Simplified error handling by leveraging context object
• Added action name constants for better maintainability

Improved Error Handling

• Consolidated error handling pattern using context spread
• Reduced parameter passing in error functions
• More consistent error handling across actions

Impact

• Maintainability: Reduced code duplication and improved organization
• Debugging: Better logging with contextual information
• Consistency: Unified patterns across action handlers
• Type Safety: Better TypeScript usage with proper type imports