fix: Correct handling of dependencies between subtasks

This commit fixes an issue with the dependency management system where
dependencies between subtasks of the same parent task were not being
handled correctly. Previously, when trying to add a dependency between
subtasks (e.g., making 23.8 depend on 23.13), the system incorrectly
interpreted it as a circular dependency of the parent task depending
on itself.

Changes:
- Modified add-dependency and remove-dependency commands to preserve
  string format for subtask IDs containing dots instead of converting
  them to integers
- Updated dependency detection logic to properly handle string-based
  subtask IDs
- Added specific tests verifying both successful dependency chains
  and circular dependency detection between subtasks of the same parent

The fix ensures proper task ordering for development workflows where
related subtasks must be completed in sequence (like establishing tests
before implementing a feature). It maintains backward compatibility with
existing task structures while correctly enforcing dependency chains
within subtask groups.

Tests:
- Added tests for valid dependency chains between subtasks of the same parent
- Added tests for circular dependency detection in subtask relationships
- Added specific test for the 23.8->23.13->23.10 subtask dependency chain

Resolves the issue where the suggested task development workflow couldn't
be properly enforced through the dependency management system.

tasks/task_023.txt

@@ -223,7 +223,7 @@ Testing approach:
 - Benchmark performance improvements from SDK integration.
 
 ## 8. Implement Direct Function Imports and Replace CLI-based Execution [in-progress]
-### Dependencies: None
+### Dependencies: 23.13
 ### Description: Refactor the MCP server implementation to use direct Task Master function imports instead of the current CLI-based execution using child_process.spawnSync. This will improve performance, reliability, and enable better error handling.
 ### Details:
 1. Create a new module to import and expose Task Master core functions directly
@@ -247,7 +247,7 @@ Testing approach:
 8. Create unit tests for context management and caching functionality
 
 ## 10. Enhance Tool Registration and Resource Management [in-progress]
-### Dependencies: 23.1
+### Dependencies: 23.1, 23.8
 ### Description: Refactor tool registration to follow FastMCP best practices, using decorators and improving the overall structure. Implement proper resource management for task templates and other shared resources.
 ### Details:
 1. Update registerTaskMasterTools function to use FastMCP's decorator pattern
@@ -272,7 +272,7 @@ Testing approach:
 1. Design structured log format for consistent parsing\n2. Implement different log levels (debug, info, warn, error)\n3. Add request/response logging middleware\n4. Implement correlation IDs for request tracking\n5. Add performance metrics logging\n6. Configure log output destinations (console, file)\n7. Document logging patterns and usage
 
 ## 13. Create Testing Framework and Test Suite [pending]
-### Dependencies: 23.1, 23.3, 23.8
+### Dependencies: 23.1, 23.3
 ### Description: Implement a comprehensive testing framework for the MCP server, including unit tests, integration tests, and end-to-end tests.
 ### Details:
 1. Set up Jest testing framework with proper configuration\n2. Create MCPTestClient for testing FastMCP server interaction\n3. Implement unit tests for individual tool functions\n4. Create integration tests for end-to-end request/response cycles\n5. Set up test fixtures and mock data\n6. Implement test coverage reporting\n7. Document testing guidelines and examples