Feature Request: Add "Start Date" field for tasks

[RUS29TAM]

Feature Request: Add "Start Date" field for tasks

Problem

Currently, the Gantt chart plugin shows all tasks starting on the same day, which limits realistic project planning. Professional project management requires scheduling tasks with different start dates.

Proposed Solution

Add a "Start Date" field to tasks alongside the existing "Due Date" field. This would allow:

1. Tasks to be displayed on the Gantt chart with proper timelines
2. Better project scheduling and resource allocation
3. More professional-looking project plans

Implementation Ideas

• Add "Start Date" to task properties/editor
• Display on Gantt chart as a separate bar or highlighted period
• Allow sorting by start date
• Optional: Calculate duration automatically (End Date - Start Date)

Context

This suggestion comes from user feedback and would bring Joplin closer to professional project management tools while maintaining its simplicity.

This feedback was discussed with @Scrayil who suggested creating this issue.

Priority: Medium - Would significantly enhance project planning capabilities
Complexity: Medium - Adds new field and timeline logic but builds on existing date infrastructure