feat(admin): implement delete functionality for Falukant regions and update UI components

backend/migrations-active/20260813000000-repair-bisaya-baynte-srs-answer.cjs

@@ -0,0 +1,63 @@
+'use strict';
+
+/**
+ * Older generated SRS data contained the number word "Baynte" as the
+ * currency phrase "20 Peso". Baynte itself means twenty, so the expected
+ * answer must be the number without a currency unit.
+ */
+module.exports = {
+  async up(queryInterface) {
+    await queryInterface.sequelize.query(`
+      WITH affected AS (
+        SELECT
+          id,
+          user_id,
+          course_id,
+          lesson_id,
+          direction,
+          CASE
+            WHEN LOWER(TRIM(learning)) = 'baynte' THEN 'baynte'
+            ELSE '20'
+          END AS corrected_learning,
+          CASE
+            WHEN LOWER(TRIM(reference)) = 'baynte' THEN 'baynte'
+            ELSE '20'
+          END AS corrected_reference
+        FROM community.vocab_srs_item
+        WHERE (LOWER(TRIM(learning)) = 'baynte' AND LOWER(TRIM(reference)) IN ('20 peso', '20 pesos'))
+           OR (LOWER(TRIM(reference)) = 'baynte' AND LOWER(TRIM(learning)) IN ('20 peso', '20 pesos'))
+      ),
+      keyed AS (
+        SELECT
+          affected.*,
+          ENCODE(DIGEST(CONCAT_WS(
+            '|',
+            course_id::text,
+            COALESCE(lesson_id::text, 'course'),
+            UPPER(direction),
+            corrected_learning,
+            corrected_reference
+          ), 'sha1'), 'hex') AS corrected_item_key
+        FROM affected
+      )
+      UPDATE community.vocab_srs_item item
+      SET learning = keyed.corrected_learning,
+          reference = keyed.corrected_reference,
+          item_key = keyed.corrected_item_key,
+          updated_at = NOW()
+      FROM keyed
+      WHERE item.id = keyed.id
+        AND NOT EXISTS (
+          SELECT 1
+          FROM community.vocab_srs_item duplicate
+          WHERE duplicate.user_id = keyed.user_id
+            AND duplicate.item_key = keyed.corrected_item_key
+            AND duplicate.id <> keyed.id
+        );
+    `);
+  },
+
+  async down() {
+    // The old answer was semantically incorrect and must not be restored.
+  },
+};