refactor(exercises): standardize answer language handling across exercise scripts

- Introduced a mechanism to infer answer language based on question phrasing in multiple exercise scripts, enhancing consistency in exercise data.
- Updated question formats to clarify the intent of exercises, improving user understanding and engagement.
- Streamlined the code for better maintainability and clarity in exercise generation processes.

frontend/src/views/social/VocabLessonView.vue

@@ -1251,9 +1251,53 @@ export default {
     },
     lessonVocab() {
       const vocabByReference = new Map();
+      const targetTokenWeight = new Map();
+      const nativeTokenWeight = new Map();
+      const addTokens = (text, map, weight = 1) => {
+        const tokens = String(text || '')
+          .toLowerCase()
+          .normalize('NFKC')
+          .replace(/[\p{P}\p{S}]+/gu, ' ')
+          .split(/\s+/)
+          .map((t) => t.trim())
+          .filter((t) => t.length >= 2);
+        tokens.forEach((token) => {
+          map.set(token, (map.get(token) || 0) + weight);
+        });
+      };
+      const sideScore = (text, map) => {
+        const tokens = String(text || '')
+          .toLowerCase()
+          .normalize('NFKC')
+          .replace(/[\p{P}\p{S}]+/gu, ' ')
+          .split(/\s+/)
+          .map((t) => t.trim())
+          .filter((t) => t.length >= 2);
+        return tokens.reduce((sum, token) => sum + (map.get(token) || 0), 0);
+      };
+      (this.normalizedCorePatterns || []).forEach((p) => {
+        addTokens(p?.target, targetTokenWeight, 3);
+        addTokens(p?.gloss, nativeTokenWeight, 3);
+      });
+      (this.importantVocab || []).forEach((v) => {
+        addTokens(v?.reference, targetTokenWeight, 1);
+        addTokens(v?.learning, nativeTokenWeight, 1);
+      });
+      const orientPair = (learning, reference) => {
+        const l = String(learning || '').trim();
+        const r = String(reference || '').trim();
+        if (!l || !r) return { learning: l, reference: r };
+        const directScore = sideScore(r, targetTokenWeight) + sideScore(l, nativeTokenWeight);
+        const swappedScore = sideScore(l, targetTokenWeight) + sideScore(r, nativeTokenWeight);
+        if (swappedScore > directScore) {
+          return { learning: r, reference: l };
+        }
+        return { learning: l, reference: r };
+      };
       const addEntry = (entry) => {
-        const reference = String(entry?.reference || '').trim();
-        const learning = String(entry?.learning || '').trim();
+        const oriented = orientPair(entry?.learning, entry?.reference);
+        const reference = String(oriented.reference || '').trim();
+        const learning = String(oriented.learning || '').trim();
         if (!reference) return;
         const key = this.normalizeLessonVocabTerm(reference);
         if (!vocabByReference.has(key)) {