fix: normalize engineering checks across units

Convert pump-depth vs rod-length mismatch gating to meter-equivalent comparisons, add imperial coverage, and correct rod material mapping with exported helper tests while refreshing related GUI/docs copy.

Made-with: Cursor

solver-api/src/solverClient.js

@@ -53,12 +53,14 @@ export function deriveTrajectoryFrictionMultiplier(model) {
 
 function rodTypeToProps(typeCode) {
   const t = Math.round(typeCode);
-  if (t === 2) {
+  if (t === 3) {
     return { E: FIBERGLASS_E, rho: FIBERGLASS_RHO };
   }
   return { E: STEEL_E, rho: STEEL_RHO };
 }
 
+export { rodTypeToProps };
+
 function buildRodNodes(model) {
   const nx = 48;
   const nodes = nx + 1;

solver-api/tests/solverClient.test.js

@@ -0,0 +1,26 @@
+import { describe, expect, it } from "vitest";
+import { rodTypeToProps } from "../src/solverClient.js";
+
+describe("solverClient rod type mapping", () => {
+  it("maps fiberglass rod type 3 to fiberglass properties", () => {
+    expect(rodTypeToProps(3)).toEqual({
+      E: 5.5e9,
+      rho: 1900
+    });
+  });
+
+  it("maps sinker and steel rod types to steel-like properties", () => {
+    expect(rodTypeToProps(2)).toEqual({
+      E: 2.05e11,
+      rho: 7850
+    });
+    expect(rodTypeToProps(0)).toEqual({
+      E: 2.05e11,
+      rho: 7850
+    });
+    expect(rodTypeToProps(1)).toEqual({
+      E: 2.05e11,
+      rho: 7850
+    });
+  });
+});