feat(topics): restore topic taxonomy workflow

tests/front-submit/topics.test.cjs

@@ -0,0 +1,22 @@
+const assert = require('node:assert/strict');
+const { execFileSync } = require('node:child_process');
+const path = require('node:path');
+const test = require('node:test');
+
+const result = JSON.parse(execFileSync('php', [path.join(__dirname, 'topics-harness.php')], { encoding: 'utf8' }));
+
+test('topic whitelist includes descendants and preserves a selected child without its parent', () => {
+  assert.deepEqual(result.root_tree, [
+    { id: 1, depth: 0 },
+    { id: 2, depth: 1 },
+    { id: 3, depth: 1 },
+  ]);
+  assert.deepEqual(result.child_tree, [{ id: 2, depth: 0 }]);
+  assert.match(result.orphan_html, /name="topics\[\]" value="2"/);
+});
+
+test('topic submissions accept only existing terms within the configured whitelist', () => {
+  assert.deepEqual(result.filtered, [2]);
+  assert.deepEqual(result.disabled_tree, []);
+  assert.deepEqual(result.disabled_filtered, []);
+});