Right-click context menu and drawing functionality bugs

[iamAmer]

There are several issues with the 2D canvas drawing application related to right-click behavior:

Problem 1: Right-click on grid gaps creates unwanted points

• When right-clicking on the gaps between grid lines, a point is created
• No context menu appears
• Drawing functionality continues to work normally

Problem 2: Right-click on grid lines shows multiple context menus

• When right-clicking on the grid lines themselves, both the browser's default context menu and the custom context menu appear
• After this happens, drawing functionality stops working completely
• This issue persists even after drawing for some time, not just on the first interaction

Problem 3: Points remain after deleting lines

• When deleting a line, sometimes points (vertices) remain on the canvas
• These orphaned vertices cannot be deleted through the interface
• This creates visual clutter and potential confusion for users

Expected Behavior:

1. Right-click on grid gaps should not create points and should show appropriate context menu or none at all
2. Right-click on grid lines should only show custom context menu (no browser default menu)
3. Drawing should continue to work after any right-click interaction
4. When deleting a line, associated vertices should be properly cleaned up if they're no longer connected to other lines

Steps to Reproduce:

For Problem 1:

1. Reload the page
2. Right-click on the gaps between grid lines
3. Observe that a point is created but no context menu appears
4. Verify drawing still works

For Problem 2:

1. Reload the page
2. Right-click on the grid lines
3. Observe both context menus appearing
4. Try to draw - drawing functionality should be broken

For Problem 3:

1. Draw multiple lines that share vertices
2. Delete one line
3. Check if orphaned vertices remain that cannot be deleted

[mfranzon]

Thank you for summarising the main problems on the 2d view. I'll go with sub-issues from this one to solve them one at a time.

[pcolt]

Problem 1 and 2 should be solved if PR #45 is merged following my last review