feat(vocab): enrich core patterns with glosses in VocabService and VocabLessonView

- Implemented a new method in VocabService to enhance core patterns with glosses derived from extracted vocabulary, improving the clarity of vocabulary entries.
- Updated the VocabLessonView to utilize the enriched core patterns, ensuring that glosses are displayed alongside vocabulary targets for better user comprehension.
- Refactored vocabulary preparation logic to integrate glosses seamlessly, enhancing the overall user experience during vocabulary lessons.

backend/services/vocabService.js

@@ -321,6 +321,32 @@ export default class VocabService {
     return n ? n.target : '';
   }
 
+  _enrichCorePatternsWithGloss(corePatterns = [], extractedVocabs = []) {
+    const glossByReference = new Map();
+
+    extractedVocabs.forEach((item) => {
+      const reference = this._normalizeLexeme(item?.reference);
+      const learning = String(item?.learning || '').trim();
+      if (!reference || !learning) {
+        return;
+      }
+      if (!glossByReference.has(reference)) {
+        glossByReference.set(reference, learning);
+      }
+    });
+
+    return corePatterns
+      .map((entry) => this._normalizeCorePatternEntry(entry))
+      .filter(Boolean)
+      .map((entry) => {
+        if (entry.gloss) {
+          return entry;
+        }
+        const gloss = glossByReference.get(this._normalizeLexeme(entry.target)) || '';
+        return gloss ? { ...entry, gloss } : entry;
+      });
+  }
+
   _normalizeStructuredList(value, keys = ['title', 'text']) {
     if (!value) return [];
     if (Array.isArray(value)) {
@@ -533,7 +559,11 @@ export default class VocabService {
     const uniquePatterns = [...new Set(patterns.map((item) => String(item || '').trim()).filter(Boolean))];
 
     const learningGoals = this._normalizeStringList(plainLesson.learningGoals);
-    const corePatterns = this._normalizeCorePatternList(plainLesson.corePatterns);
+    const extractedTrainerVocabs = this._extractTrainerVocabsFromExercises(grammarExercises);
+    const corePatterns = this._enrichCorePatternsWithGloss(
+      this._normalizeCorePatternList(plainLesson.corePatterns),
+      extractedTrainerVocabs
+    );
     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']);
@@ -548,7 +578,10 @@ export default class VocabService {
           ],
       corePatterns: corePatterns.length > 0
         ? corePatterns
-        : uniquePatterns.slice(0, 5).map((s) => ({ target: String(s || '').trim(), gloss: '' })).filter((p) => p.target),
+        : this._enrichCorePatternsWithGloss(
+            uniquePatterns.slice(0, 5).map((s) => ({ target: String(s || '').trim(), gloss: '' })).filter((p) => p.target),
+            extractedTrainerVocabs
+          ),
       grammarFocus: grammarFocus.length > 0 ? grammarFocus : uniqueGrammarExplanations.slice(0, 4),
       speakingPrompts: explicitSpeakingPrompts.length > 0 ? explicitSpeakingPrompts : speakingPrompts.slice(0, 4),
       practicalTasks: practicalTasks.length > 0