Standardize phase type labels

tests/circuit-power-calculation.test.ts

@@ -7,6 +7,7 @@ import {
 import {
   resolveCircuitPhaseType,
   resolveProjectVoltage,
+  normalizeKnownElectricalPhaseType,
 } from "../src/domain/services/project-voltage.service.js";
 
 describe("circuit power calculation", () => {
@@ -43,5 +44,17 @@ describe("project voltage derivation", () => {
     assert.equal(resolveCircuitPhaseType("unassigned", []), "single_phase");
     assert.equal(resolveCircuitPhaseType("unassigned", [null]), "single_phase");
   });
+
+  it("normalizes known legacy phase labels without guessing unknown values", () => {
+    assert.equal(normalizeKnownElectricalPhaseType("1phasig"), "single_phase");
+    assert.equal(normalizeKnownElectricalPhaseType("1-phasig"), "single_phase");
+    assert.equal(normalizeKnownElectricalPhaseType("3phase"), "three_phase");
+    assert.equal(normalizeKnownElectricalPhaseType("3-phasig"), "three_phase");
+    assert.equal(normalizeKnownElectricalPhaseType(null), null);
+    assert.throws(
+      () => normalizeKnownElectricalPhaseType("zweiphasig"),
+      /Unknown electrical phase type/
+    );
+  });
 });