feat: implement individual Note Sync Mode and Dashboard

[carlos-otero]

• Added "Note Sync Mode" allowing tasks to be synced as individual Markdown files.
• Implemented NoteSearcher to parse task metadata (ID, due date, priority, tags) from frontmatter.
• Enhanced Processor to handle bidirectional sync for task notes, including file creation and deletion.
• Added a command to generate a "Vikunja Dashboard" note using Dataview.
• Improved task comparison logic to handle null/undefined fields and prevent redundant updates.
• Fixed date formatting issues between Obsidian YAML and Vikunja ISO strings.
• Added debouncing to editor changes to improve performance and sync stability.