refactor(theme-studio): extract control factories to controls.js, drop dead previewFaceAttrs

I split the custom dropdown, detail-editor, and expander factories out of app.js into controls.js (205 lines), spliced back at a CONTROLS_J token by generate.py. The token sits at the exact extraction point, so the assembled page is byte-identical and every gate passes unchanged. app.js drops from 927 to 721 lines.

I also removed previewFaceAttrs (function, export, and test). It was test-only dead code whose docstring stalely claimed the gate calls it. The gate uses assertPreviewFaces instead.

1 files changed, 1 insertions, 10 deletions

diff --git a/scripts/theme-studio/test-locate.mjs b/scripts/theme-studio/test-locate.mjs
index 5e36aa808..09d15b8bc 100644
--- a/scripts/theme-studio/test-locate.mjs
+++ b/scripts/theme-studio/test-locate.mjs
@@ -8,7 +8,7 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import {
-  buildLocateRegistry, locateFaceMeta, formatLocateTitle, previewFaceAttrs, isLocateOnPane,
+  buildLocateRegistry, locateFaceMeta, formatLocateTitle, isLocateOnPane,
 } from './app-core.js';
 
 // A constructed model: two package apps that BOTH own a face literally named
@@ -142,15 +142,6 @@ test('formatLocateTitle: Error — an unassigned meta reads "unassigned"', () =>
   assert.equal(formatLocateTitle(locateFaceMeta('org-faces', 'ghost', reg)), 'ghost, unassigned');
 });
 
-// --- previewFaceAttrs: owner-aware validation -------------------------------
-
-test('previewFaceAttrs: Normal — a known owner/face validates; a bad owner is rejected', () => {
-  const reg = buildLocateRegistry(APPS, PKGMAP, UIMAP, MAP);
-  assert.ok(previewFaceAttrs('org-faces', 'org-todo', reg), 'known face validates');
-  assert.equal(previewFaceAttrs('org-mode', 'minibuffer-prompt', reg), null, 'a UI face under a package owner is rejected');
-  assert.equal(previewFaceAttrs('nope', 'org-todo', reg), null, 'an unknown owner is rejected');
-});
-
 // --- lifecycle + perf -------------------------------------------------------
 
 test('buildLocateRegistry: lifecycle — a rebuild after an edit reflects the new value', () => {