feat(mcp): Add tagInfo to responses and integrate ContextGatherer

Enhances the MCP server to include 'tagInfo' (currentTag, availableTags) in all tool responses, providing better client-side context.

- Introduces a new 'ContextGatherer' utility to standardize the collection of file, task, and project context for AI-powered commands. This refactors several task-manager modules ('expand-task', 'research', 'update-task', etc.) to use the new utility.

- Fixes an issue in 'get-task' and 'get-tasks' MCP tools where the 'projectRoot' was not being passed correctly, preventing tag information from being included in their responses.

- Adds subtask '103.17' to track the implementation of the task template importing feature.

- Updates documentation ('.cursor/rules', 'docs/') to align with the new tagged task system and context gatherer logic.

.cursor/rules/taskmaster.mdc

@@ -11,6 +11,8 @@ This document provides a detailed reference for interacting with Taskmaster, cov
 
 **Important:** Several MCP tools involve AI processing... The AI-powered tools include `parse_prd`, `analyze_project_complexity`, `update_subtask`, `update_task`, `update`, `expand_all`, `expand_task`, and `add_task`.
 
+**Tagged Task Lists System:** Task Master now supports tagged task lists for multi-context task management. Existing projects automatically migrate to use a "master" tag with zero disruption. All commands continue to work unchanged while providing the foundation for enhanced multi-context workflows. MCP tools will be updated for full tagged support in Part 2 of the implementation.
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 ## Initialization & Setup