Extends the 4-corner L-bracket handles with 4 tick-mark edge handles
(short lines along each edge), enabling single-axis resize from any edge.
Updates applyHandleDrag to route each handle to the correct axis.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- 4 corner-only handles (nw/ne/sw/se), no edge midpoints
- Each handle renders as two short perpendicular lines meeting at the corner
(10px arms, navy, square linecap) — no fill, no box
- Thin dashed selection border added to SVG overlay to signal edit mode
- Simplify applyHandleDrag to remove dead n/s/e/w branches
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Hides block number badges and disables hover/active visual feedback
when dimmed=true. Click handlers remain active for scroll-sync.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
