feat(bisaya-course): add didactics fragments for "Haus & Familie" lessons

- Introduced comprehensive didactics snippets for the "Haus & Familie" lesson, including learning goals, core patterns, grammar focus, speaking prompts, and practical tasks.
- Updated the lesson retrieval logic to incorporate these new fragments as a fallback for core patterns, enhancing the robustness of lesson content delivery.
- Modified the vocab service to utilize the new didactics fragments, ensuring a seamless integration into the existing lesson structure.

backend/services/vocabService.js

@@ -12,7 +12,7 @@ import UserParam from '../models/community/user_param.js';
 import { sequelize } from '../utils/sequelize.js';
 import { notifyUser } from '../utils/socket.js';
 import { Op } from 'sequelize';
-import { BISAYA_PHASE1_DIDACTICS } from '../scripts/bisaya-course-phase1.js';
+import { BISAYA_PHASE1_DIDACTICS, BISAYA_DIDACTICS_FRAGMENTS } from '../scripts/bisaya-course-phase1.js';
 
 export default class VocabService {
   _normalizeIsoDate(value) {
@@ -979,13 +979,26 @@ export default class VocabService {
     const learningGoals = this._normalizeStringList(plainLesson.learningGoals);
     const extractedTrainerVocabs = this._extractTrainerVocabsFromExercises(grammarExercises);
     const phase1FallbackCorePatterns = BISAYA_PHASE1_DIDACTICS[plainLesson.title]?.corePatterns || [];
-    const corePatterns = this._mergeCorePatternGlosses(
+    let resolvedCorePatterns = this._mergeCorePatternGlosses(
       this._enrichCorePatternsWithGloss(
         this._normalizeCorePatternList(plainLesson.corePatterns),
         extractedTrainerVocabs
       ),
       phase1FallbackCorePatterns
     );
+    if (
+      !resolvedCorePatterns.length
+      && BISAYA_DIDACTICS_FRAGMENTS[plainLesson.title]?.corePatterns?.length
+    ) {
+      const frag = BISAYA_DIDACTICS_FRAGMENTS[plainLesson.title];
+      resolvedCorePatterns = this._mergeCorePatternGlosses(
+        this._enrichCorePatternsWithGloss(
+          this._normalizeCorePatternList(frag.corePatterns),
+          extractedTrainerVocabs
+        ),
+        phase1FallbackCorePatterns
+      );
+    }
     const grammarFocus = this._normalizeStructuredList(plainLesson.grammarFocus, ['title', 'text', 'example']);
     const explicitSpeakingPrompts = this._normalizeStructuredList(plainLesson.speakingPrompts, ['title', 'prompt', 'cue']);
     const practicalTasks = this._normalizeStructuredList(plainLesson.practicalTasks, ['title', 'text']);
@@ -998,8 +1011,8 @@ export default class VocabService {
             'Ein bis zwei Satzmuster aktiv anwenden.',
             'Kurze Sätze oder Mini-Dialoge zum Thema selbst bilden.'
           ],
-      corePatterns: corePatterns.length > 0
-        ? corePatterns
+      corePatterns: resolvedCorePatterns.length > 0
+        ? resolvedCorePatterns
         : this._mergeCorePatternGlosses(
             this._enrichCorePatternsWithGloss(
               uniquePatterns.slice(0, 5).map((s) => ({ target: String(s || '').trim(), gloss: '' })).filter((p) => p.target),