Replace plain rectangles with tap/faucet SVG graphics for source nodes
(draggable valve handle, metallic gradients, animated water stream) and
trapezoid vessel shapes for funnel nodes (water fill, wave surface,
threshold markers, overflow lips with pour animations). Overflow pipes
now render as 3-layer bezier connections from vessel lips. Add amount
popover with date scheduling, event delegation for interactivity, and
rAF-throttled valve dragging.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>