dots property

Optional list of drawable dots (connection points) along the wire path.

Dots represent junction points where multiple wires meet or pass through:

• Connection endpoints (source/target ports are NOT dots)
• Points where 3+ wires converge
• T-junction points (2 wires where at least one passes through)

Exclusions (no dot):

• Simple corners where 2 wires meet at both endpoints (no extent overlap)

Rules for dot inclusion (from schematic_canvas.dart):

1. Always draw dot if 3+ edges are incident
2. For exactly 2 edges: draw dot only if extent overlap (T-junction)
   • Draw if at least one edge is NOT just an endpoint
   • Skip if both edges meet at both of their endpoints (simple corner)

Benefits:

• Can be culled based on wire bounding box for efficient rendering
• Can be colored when wire is selected (orange when edges are selected)
• Provides visual feedback for wire connections
• Enables hit-testing for wire selection
• Optional to support different rendering backends (some may not need dots)