feat(CalendarView): enhance training slot merging and event normalization

- Added a new method to normalize training time keys, improving consistency in event handling.
- Updated the logic for merging recurring training slots to include only relevant events, enhancing calendar management.
- Improved subtitle handling for merged training slots to reflect recurring status and additional details, providing clearer event information.

frontend/src/views/CalendarView.vue

@@ -284,21 +284,33 @@ export default {
 
       this.loading = false;
     },
+    normalizeTrainingTimeKey(time) {
+      return String(time || '')
+        .trim()
+        .replace(/[\u2013\u2012\u2212]/g, '-')
+        .replace(/\s*-\s*/g, '-')
+        .replace(/\s+/g, '');
+    },
     /**
-     * Mehrere regelmäßige Trainingszeiten mit identischem Wochentag und gleichem Uhrzeit-Fenster
-     * (z. B. parallel genutzte Gruppen / Dubletten) zu einem Kalendereintrag zusammenführen.
+     * Alle Trainings-Einträge (Tagebuch + regelmäßige Zeiten) mit gleichem Kalendertag und gleichem
+     * Zeitfenster-Text zu einem Eintrag zusammenführen (z. B. Dublette „Training“ + Gruppen).
      */
     mergeRecurringTrainingSlots(events) {
       const genericTitle = (t) => !t || /^training$/i.test(String(t).trim());
       const slotMap = new Map();
       const passthrough = [];
       for (const e of events) {
-        if (e.type !== 'training' || !e.isRecurringTraining || !e.time || !e.date) {
+        if (e.type !== 'training' || !e.date) {
+          passthrough.push(e);
+          continue;
+        }
+        const timeKey = this.normalizeTrainingTimeKey(e.time);
+        if (!timeKey) {
           passthrough.push(e);
           continue;
         }
         const dk = this.toDateKey(e.date);
-        const slotKey = `${dk}|${e.time}`;
+        const slotKey = `${dk}|${timeKey}`;
         if (!slotMap.has(slotKey)) {
           slotMap.set(slotKey, []);
         }
@@ -316,12 +328,25 @@ export default {
         const specific = rawTitles.filter((t) => !genericTitle(t));
         const titleJoined = specific.length ? specific.join(' · ') : (rawTitles.join(' · ') || base.title);
         const safeIdKey = slotKey.replace(/\|/g, '-');
+        const hasRecurring = sorted.some((x) => x.isRecurringTraining);
+        const otherSubtitles = [...new Set(
+          sorted.map((x) => String(x.subtitle || '').trim()).filter((s) => s && s !== 'Regelmäßige Trainingszeit')
+        )];
+        let subtitleJoined = '';
+        if (hasRecurring) {
+          subtitleJoined = otherSubtitles.length
+            ? `Regelmäßige Trainingszeit · ${otherSubtitles.join(' · ')}`
+            : 'Regelmäßige Trainingszeit';
+        } else {
+          subtitleJoined = otherSubtitles.join(' · ') || String(base.subtitle || '').trim() || '';
+        }
         mergedSlots.push({
           ...base,
           id: `training-merged-${safeIdKey}`,
           title: titleJoined,
-          subtitle: 'Regelmäßige Trainingszeit',
-          startsAt: Math.min(...sorted.map((x) => x.startsAt))
+          subtitle: subtitleJoined,
+          startsAt: Math.min(...sorted.map((x) => x.startsAt)),
+          isRecurringTraining: hasRecurring
         });
       }
       return [...passthrough, ...mergedSlots];