Display Documentation as Read-Only text in flow canvas (Microflows, Nanoflows, Rules...)

# Problem

Documentation is hidden in Properties panel > rarely consulted > developers lose context.

# Solution

Show documentation as read-only text in canvas (top-left corner), like the attached mockup.

# Benefits

• Instant visibility without switching panels
• Encourages developers to actually use the Documentation field
• Better team collaboration
• Cleaner canvas (less annotation clutter)
• Applies to: Microflows, Nanoflows, Rules, others

# Image