test: add suites for accentColor (color math) + matrix-uia (auth flows) (+15)

- utils/accentColor (8): hexToRgb parsing, lighten/darken channel math, rgba
  clamping, WCAG relativeLuminance (black=0/white=1), contrastingText threshold,
  varNameFromToken, and derivePrimaryPalette's full 10-token output.
- utils/matrix-uia (7): UIA flow helpers — getSupportedUIAFlows,
  completed/params/session/errcode/error accessors, getUIAFlowForStages
  (incl. the single-extra-dummy rule), has/requiredStageInFlows, and
  getLoginTermUrl language fallback.

Full suite now 123 tests, all passing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/utils/accentColor.test.ts

@@ -0,0 +1,68 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  hexToRgb,
+  lighten,
+  darken,
+  rgba,
+  relativeLuminance,
+  contrastingText,
+  varNameFromToken,
+  derivePrimaryPalette,
+} from './accentColor';
+
+test('hexToRgb parses 6-digit hex (with/without #, trimmed)', () => {
+  assert.deepEqual(hexToRgb('#ff8800'), { r: 255, g: 136, b: 0 });
+  assert.deepEqual(hexToRgb('ff8800'), { r: 255, g: 136, b: 0 });
+  assert.deepEqual(hexToRgb('  #FF8800  '), { r: 255, g: 136, b: 0 });
+  assert.equal(hexToRgb('#fff'), undefined); // 3-digit not supported
+  assert.equal(hexToRgb('nope'), undefined);
+});
+
+test('lighten moves channels toward white', () => {
+  assert.deepEqual(lighten({ r: 255, g: 0, b: 0 }, 0.5), { r: 255, g: 127.5, b: 127.5 });
+  assert.deepEqual(lighten({ r: 0, g: 0, b: 0 }, 1), { r: 255, g: 255, b: 255 });
+  assert.deepEqual(lighten({ r: 10, g: 20, b: 30 }, 0), { r: 10, g: 20, b: 30 });
+});
+
+test('darken moves channels toward black', () => {
+  assert.deepEqual(darken({ r: 200, g: 100, b: 50 }, 0.5), { r: 100, g: 50, b: 25 });
+  assert.deepEqual(darken({ r: 255, g: 255, b: 255 }, 1), { r: 0, g: 0, b: 0 });
+  assert.deepEqual(darken({ r: 10, g: 20, b: 30 }, 0), { r: 10, g: 20, b: 30 });
+});
+
+test('rgba formats and clamps channels', () => {
+  assert.equal(rgba({ r: 255, g: 136, b: 0 }, 0.5), 'rgba(255, 136, 0, 0.5)');
+  assert.equal(rgba({ r: 300, g: -5, b: 128 }, 1), 'rgba(255, 0, 128, 1)');
+});
+
+test('relativeLuminance: black is 0, white is 1', () => {
+  assert.ok(Math.abs(relativeLuminance({ r: 0, g: 0, b: 0 })) < 1e-9);
+  assert.ok(Math.abs(relativeLuminance({ r: 255, g: 255, b: 255 }) - 1) < 1e-9);
+  // green contributes more than blue (per WCAG coefficients)
+  assert.ok(relativeLuminance({ r: 0, g: 255, b: 0 }) > relativeLuminance({ r: 0, g: 0, b: 255 }));
+});
+
+test('contrastingText picks black on light, white on dark', () => {
+  assert.equal(contrastingText({ r: 255, g: 255, b: 255 }), '#000');
+  assert.equal(contrastingText({ r: 0, g: 0, b: 0 }), '#fff');
+});
+
+test('varNameFromToken extracts the CSS var name', () => {
+  assert.equal(varNameFromToken('var(--oq6d07f)'), '--oq6d07f');
+  assert.equal(varNameFromToken('--bare'), undefined);
+  assert.equal(varNameFromToken('not a token'), undefined);
+});
+
+test('derivePrimaryPalette produces the full Primary token set', () => {
+  const palette = derivePrimaryPalette({ r: 255, g: 136, b: 0 });
+  assert.equal(Object.keys(palette).length, 10);
+  assert.equal(palette.Main, '#ff8800');
+  assert.equal(palette.MainLine, '#ff8800');
+  assert.equal(palette.Container, 'rgba(255, 136, 0, 0.12)');
+  assert.equal(palette.ContainerLine, 'rgba(255, 136, 0, 0.4)');
+  assert.equal(palette.OnMain, contrastingText({ r: 255, g: 136, b: 0 }));
+  // hover/active are valid 6-digit hex strings
+  assert.match(palette.MainHover, /^#[0-9a-f]{6}$/);
+  assert.match(palette.MainActive, /^#[0-9a-f]{6}$/);
+});