Redesigned phoenix inspect with focus mode, SVG lines, and graph overlay
Three major UX improvements to the pipeline visualisation:
1. Focus mode: clicking any node hides everything unconnected.
Only the causal chain remains visible across all 5 columns.
Toggling All/Focus in the header switches between full view
and filtered view.
2. SVG connection lines: bezier curves drawn between connected
cards across columns. Thicker/brighter lines for direct
connections to the selected node. Lines update on scroll/resize.
3. Graph overlay (press G or click ⬡ Graph): full-screen layered
graph showing just the selected subgraph with proper
node positioning by column and SVG edge routing.
Interaction: click a node → auto-enters focus mode → shows only
its chain with drawn connections. Press G for graph view.
Escape to back out. Click empty space to deselect.