feat(exercises): enhance context in gap fill exercises and update migration for route descriptions

backend/scripts/create-bisaya-course-content.js

@@ -599,7 +599,8 @@ function buildGapExercise(lessonTitle, pattern) {
 
 function buildContextGapExercise(lesson, didactics, pattern) {
   const speakingPrompt = Array.isArray(didactics.speakingPrompts) ? didactics.speakingPrompts[0] : null;
-  const cue = normalizeText(speakingPrompt?.cue || '').toLowerCase();
+  const scenarioCue = normalizeText(speakingPrompt?.cue || '');
+  const cue = scenarioCue.toLowerCase();
   // A contextual prompt must test a pattern that actually occurs in its
   // scenario. Otherwise a cultural keyword such as "respeto" can be paired
   // with an invitation-declining situation.
@@ -608,14 +609,21 @@ function buildContextGapExercise(lesson, didactics, pattern) {
     .find((candidate) => candidate && cue.includes(normalizeText(candidate).toLowerCase()));
   // Do not hide a complete sentence behind one blank. Learners need enough
   // visible context to know which word or short phrase belongs in the gap.
-  const gapExercise = scenarioPattern
-    ? buildGapExercise(lesson.title, scenarioPattern)
-    : buildGapExercise(lesson.title, pattern);
+  const scenarioSteps = scenarioCue
+    .split(/[.!?]+/)
+    .map((step) => step.trim())
+    .filter(Boolean);
+  // A multi-step cue is already the concrete scenario.  Do not reduce a
+  // route such as "Diretso. Tuo. Wala. Duol ra." to a bare direction word.
+  const gapTarget = scenarioSteps.length >= 2
+    ? scenarioCue
+    : (scenarioPattern || pattern);
+  const gapExercise = buildGapExercise(lesson.title, gapTarget);
   if (!gapExercise) return null;
 
   return {
     ...gapExercise,
-    title: `${lesson.title}: Kernmuster ergänzen`,
+    title: `${lesson.title}: Satz im Kontext ergänzen`,
     instruction: `Vervollständige die Formulierung passend zur Situation: ${getScenarioPrompt(lesson, didactics)}`
   };
 }
@@ -634,7 +642,7 @@ function buildSentenceExercise(lessonTitle, pattern) {
     instruction: 'Ordne die Wörter zu einem korrekten Bisaya-Satz.',
     questionData: {
       type: 'sentence_building',
-      question: `Baue das Kernmuster aus der Lektion "${lessonTitle}".`,
+      question: 'Ordne diese Wörter zu einem vollständigen Bisaya-Satz.',
       tokens
     },
     answerData: {