Feature/#561 add note functionality to floating bar

[gustedeveloper]

Add Note component functionality to canvas:

Implements post-it style notes on the canvas with the following features:

• Create, edit, and delete notes with optional title and mandatory description
• Drag and drop positioning on canvas
• Auto-height adjustment based on content (min: 100px, max: 300px)
• Multi-line ellipsis for overflow text
• Visual selection state with colored border
• Edit icon on hover to modify existing notes
• Persistence support with autosave
• New "Add Note" button in floating bar

Technical improvements:

• Extracted useCanvasDraggable hook to common folder for reusability (TODO: future refactor table component to use this hook)
• Updated schema model with NoteVm interface
• Backward compatibility: old schemas automatically get notes array on load
• Enhanced global CSS for textarea focus/hover states

Close #561