feat: Add timeline dependencies feature with visual connectors

[pqhung3007]

Implemented comprehensive task dependency management in Timeline layout with:

Features:

• Visual dependency connectors with SVG lines connecting related tasks
• Three dependency types support:
  • Finish-to-Start (FS): Blocking/Blocked by relations
  • Start-to-Start (SS): Starts before/after relations
  • Finish-to-Finish (FF): Finishes before/after relations
• Drag-and-drop interface for creating dependencies
  • Left handle: Creates start-to-start dependencies
  • Right handle: Creates finish-to-start or finish-to-finish dependencies
• Dependency validation with red lines for violated constraints
• Interactive dependency dialog showing relationship details on click
• Automatic relation type detection based on drag handles

Technical Implementation:

• Added new relation types: starts_before, starts_after, finishes_before, finishes_after
• TimelineDependencyPaths component for rendering dependency lines
• TimelineDraggablePath component for drag-to-create functionality
• Left/Right dependency draggable handles on timeline blocks
• DependencyDialog component for displaying relation information
• Integrated with existing relation store and API services
• Enabled isDependencyEnabled flag in timeline store

Files Modified:

• packages/types: Extended TIssueRelationTypes with new dependency types
• ce/constants: Added reverse relation mappings
• ce/store/timeline: Enabled dependency feature flag
• ce/components/gantt-chart/dependency: Implemented all dependency components

This feature helps users manage connected tasks with a clear, high-level view of task relationships, optimize resource allocation, track bottlenecks, and prevent delays by visualizing dependencies directly in the timeline.

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Improvement (change that would cause existing functionality to not work as expected)
• Code refactoring
• Performance improvements
• Documentation update

Screenshots and Media (if applicable)

Test Scenarios

References