refactor(mood): drop the orientation helper until something needs it

The inverse flag is read by the trend legend and by the assistant block;
the function that flips a value through it had no caller. It comes back
with the surface that needs a combined view, not before.

src/lib/mood/__tests__/dimensions.test.ts

@@ -5,7 +5,6 @@ import {
   MOOD_DIMENSION_MAX,
   MOOD_DIMENSION_MIN,
   getMoodDimension,
-  orientForComparison,
 } from "@/lib/mood/dimensions";
 
 describe("MOOD_DIMENSIONS", () => {
@@ -61,27 +60,3 @@ describe("MOOD_DIMENSIONS", () => {
     expect(getMoodDimension("")).toBeUndefined();
   });
 });
-
-describe("orientForComparison", () => {
-  const a1 = MOOD_DIMENSIONS[0];
-  const a2 = MOOD_DIMENSIONS[1];
-
-  it("leaves an upright dimension alone", () => {
-    expect(orientForComparison(a1, 0)).toBe(0);
-    expect(orientForComparison(a1, 7)).toBe(7);
-    expect(orientForComparison(a1, 10)).toBe(10);
-  });
-
-  it("flips the inverse dimension around the scale", () => {
-    expect(orientForComparison(a2, 0)).toBe(10);
-    expect(orientForComparison(a2, 3)).toBe(7);
-    expect(orientForComparison(a2, 10)).toBe(0);
-  });
-
-  it("answers null for an absent value rather than a neutral one", () => {
-    expect(orientForComparison(a1, null)).toBeNull();
-    expect(orientForComparison(a1, undefined)).toBeNull();
-    expect(orientForComparison(a2, null)).toBeNull();
-    expect(orientForComparison(a2, Number.NaN)).toBeNull();
-  });
-});

src/lib/mood/dimensions.ts

@@ -120,19 +120,3 @@ const BY_KEY = new Map<string, MoodDimension>(
 export function getMoodDimension(key: string): MoodDimension | undefined {
   return BY_KEY.get(key);
 }
-
-/**
- * Turn a stored value into one where "up" reads as "better".
- *
- * The only legal way to normalise an inverse dimension. Returns `null` for an
- * absent value, because an unanswered dimension is not a neutral one — the
- * whole point of leaving A2..A5 nullable is that absence stays readable as
- * absence.
- */
-export function orientForComparison(
-  dimension: MoodDimension,
-  value: number | null | undefined,
-): number | null {
-  if (typeof value !== "number" || !Number.isFinite(value)) return null;
-  return dimension.inverse ? dimension.max - value : value;
-}