Lawn Sprinkler Head-to-Head Uniformity & Hazen-Williams Pipe Pressure Solver

Deterministic Hazen-Williams friction loss (hf = 10.67 * L * Q^1.852 / (C^1.852 * D^4.87)) + Christiansen Distribution Uniformity (DU > 80%) grid engine (.svg, .dxf, .pdf, .csv) built for Hunter, Rain Bird, Toro, Netafim — zero-upload ephemeral Wasm RAM execution.