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.

scripts/modules/commands.js

@@ -471,7 +471,12 @@ function registerCommands(programInstance) {
         process.exit(1);
       }
       
-      await addDependency(tasksPath, parseInt(taskId, 10), parseInt(dependencyId, 10));
+      // Handle subtask IDs correctly by preserving the string format for IDs containing dots
+      // Only use parseInt for simple numeric IDs
+      const formattedTaskId = taskId.includes('.') ? taskId : parseInt(taskId, 10);
+      const formattedDependencyId = dependencyId.includes('.') ? dependencyId : parseInt(dependencyId, 10);
+      
+      await addDependency(tasksPath, formattedTaskId, formattedDependencyId);
     });
 
   // remove-dependency command
@@ -491,7 +496,12 @@ function registerCommands(programInstance) {
         process.exit(1);
       }
       
-      await removeDependency(tasksPath, parseInt(taskId, 10), parseInt(dependencyId, 10));
+      // Handle subtask IDs correctly by preserving the string format for IDs containing dots
+      // Only use parseInt for simple numeric IDs
+      const formattedTaskId = taskId.includes('.') ? taskId : parseInt(taskId, 10);
+      const formattedDependencyId = dependencyId.includes('.') ? dependencyId : parseInt(dependencyId, 10);
+      
+      await removeDependency(tasksPath, formattedTaskId, formattedDependencyId);
     });
 
   // validate-dependencies command