test(theme-studio): cover defensive branches and the palette generator

Added the uncovered fallback branches in app-core (migrateLegacyFace null input, normalizePkgFace's source fallback chain, mergePackagesInto's null/new-app guards, boxCss shading a relief from the bg when no box color is set) and in colormath (apca's equal-luminance return-0 and low-contrast clamp, isPureEndpointHex). New test-palette-generator-core.mjs drives planPaletteGenerator across every scheme, vibe, source mode, and the fill-gaps intents, since those internals are only reachable through the public planner. colormath branch 96 -> 99%, palette-generator-core funcs 97 -> 100%, node suite 237 tests. The remaining gaps are the deep palette-column edge branches, deferred as diminishing returns on already line-covered code.

1 files changed, 32 insertions, 0 deletions

diff --git a/scripts/theme-studio/test-app-core.mjs b/scripts/theme-studio/test-app-core.mjs
index e0d3c321a..c6473ae96 100644
--- a/scripts/theme-studio/test-app-core.mjs
+++ b/scripts/theme-studio/test-app-core.mjs
@@ -1103,3 +1103,35 @@ test('faceCss: Error — opts omitted still works', () => {
   assert.equal(faceCss({}, '#111', null),
     'color:#111;font-weight:normal;font-style:normal;text-decoration:none');
 });
+
+// --- defensive / fallback branches -------------------------------------------
+
+test('migrateLegacyFace: Boundary — null/undefined input yields an empty object', () => {
+  assert.deepEqual(migrateLegacyFace(null), {});
+  assert.deepEqual(migrateLegacyFace(undefined), {});
+});
+
+test('normalizePkgFace: Normal — source falls back through arg, d.source, then "user"', () => {
+  assert.equal(normalizePkgFace({}, 'default').source, 'default');     // arg wins
+  assert.equal(normalizePkgFace({source: 'cleared'}).source, 'cleared'); // d.source
+  assert.equal(normalizePkgFace({}).source, 'user');                   // default
+});
+
+test('mergePackagesInto: Boundary — null packages is a no-op', () => {
+  const map = {existing: {f: {fg: '#111'}}};
+  mergePackagesInto(map, null);
+  assert.deepEqual(Object.keys(map), ['existing']);
+});
+test('mergePackagesInto: Normal — a new app key is created', () => {
+  const map = {};
+  mergePackagesInto(map, {newapp: {'face-a': {fg: '#112233', source: 'user'}}});
+  assert.ok(map.newapp && map.newapp['face-a']);
+  assert.equal(map.newapp['face-a'].fg, '#112233');
+});
+
+test('boxCss: Boundary — released with no color but a bg shades from the bg', () => {
+  const fromBg = boxCss({style: 'released'}, '#808080');
+  // not the translucent no-bg fallback, and a real two-edge relief
+  assert.notEqual(fromBg, 'inset 1px 1px 0 #ffffff33,inset -1px -1px 0 #00000066');
+  assert.match(fromBg, /^inset 1px 1px 0 \S+,inset -1px -1px 0 \S+$/);
+});