feat: add task dependency management tools

Add 3 new MCP tools for managing ClickUp task dependencies:
- add_task_dependency: Create blocking/waiting dependencies between tasks
- remove_task_dependency: Remove dependency relationships
- get_task_dependencies: Retrieve task dependencies and linked tasks

Implements ClickUp API endpoints:
- POST /task/{task_id}/dependency
- DELETE /task/{task_id}/dependency
- Uses existing GET /task/{task_id} for dependency retrieval

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: stephenVertex