feat(bisaya-course): expand lesson didactics with new topics and detailed grammar focus

- Added new lesson topics including 'Überlebenssätze - Teil 1', 'Familien-Gespräche', 'Gefühle & Zuneigung', and 'Überlebenssätze - Teil 2' to enhance the curriculum.
- Updated existing lessons with more detailed learning goals, core patterns, grammar focus, speaking prompts, and practical tasks to improve learner engagement and comprehension.
- Refactored core patterns to include glosses for better understanding of vocabulary context.
- Enhanced the structure of lesson didactics to provide a more comprehensive learning experience for users.

frontend/src/views/social/VocabLessonView.vue

@@ -2385,6 +2385,7 @@ export default {
       return this.vocabTrainerStats[key];
     },
     normalizeRepeatQueue(queue = []) {
+      const repeatIntervals = this.getRepeatIntervals();
       if (!Array.isArray(queue)) {
         return [];
       }
@@ -2392,37 +2393,56 @@ export default {
         .map((entry) => ({
           key: String(entry?.key || '').trim(),
           dueAfter: Math.max(0, Number(entry?.dueAfter) || 0),
-          stageIndex: Math.max(0, Math.min(VOCAB_REPEAT_INTERVALS.length - 1, Number(entry?.stageIndex) || 0))
+          stageIndex: Math.max(0, Math.min(repeatIntervals.length - 1, Number(entry?.stageIndex) || 0))
         }))
         .filter((entry) => entry.key);
     },
+    getRepeatIntervals() {
+      const availableCount = new Set(
+        [...this.trainableLessonVocab, ...this.vocabTrainerMixedPool].map((vocab) => this.getVocabKey(vocab))
+      ).size;
+      const maxSpacing = Math.max(1, Math.min(4, availableCount - 1));
+
+      if (maxSpacing <= 1) {
+        return [1, 1, 1];
+      }
+      if (maxSpacing === 2) {
+        return [1, 1, 2];
+      }
+      if (maxSpacing === 3) {
+        return [1, 2, 3];
+      }
+      return VOCAB_REPEAT_INTERVALS;
+    },
     queueFailedVocab(vocab) {
+      const repeatIntervals = this.getRepeatIntervals();
       const key = this.getVocabKey(vocab);
       const existing = this.vocabTrainerRepeatQueue.find((entry) => entry.key === key);
       if (existing) {
-        existing.dueAfter = VOCAB_REPEAT_INTERVALS[0];
+        existing.dueAfter = repeatIntervals[0];
         existing.stageIndex = 0;
         return;
       }
       this.vocabTrainerRepeatQueue.push({
         key,
-        dueAfter: VOCAB_REPEAT_INTERVALS[0],
+        dueAfter: repeatIntervals[0],
         stageIndex: 0
       });
     },
     resolveRepeatedVocab(vocab) {
+      const repeatIntervals = this.getRepeatIntervals();
       const key = this.getVocabKey(vocab);
       const entryIndex = this.vocabTrainerRepeatQueue.findIndex((entry) => entry.key === key && entry.dueAfter <= 0);
       if (entryIndex === -1) {
         return;
       }
       const entry = this.vocabTrainerRepeatQueue[entryIndex];
-      if (entry.stageIndex >= VOCAB_REPEAT_INTERVALS.length - 1) {
+      if (entry.stageIndex >= repeatIntervals.length - 1) {
         this.vocabTrainerRepeatQueue.splice(entryIndex, 1);
         return;
       }
       entry.stageIndex += 1;
-      entry.dueAfter = VOCAB_REPEAT_INTERVALS[entry.stageIndex];
+      entry.dueAfter = repeatIntervals[entry.stageIndex];
     },
     advanceRepeatQueue(completedKey = '') {
       this.vocabTrainerRepeatQueue = this.vocabTrainerRepeatQueue