feat: implement missing placeholder functions (sleep, vitals, rest)

Implementiert 6 fehlende Platzhalter-Funktionen die im Katalog waren
aber keine Berechnung hatten.

Neue Funktionen:
- get_sleep_avg_duration(7d) → "7.5h"
- get_sleep_avg_quality(7d) → "65% (Deep+REM)"
- get_rest_days_count(30d) → "5 Ruhetage"
- get_vitals_avg_hr(7d) → "58 bpm"
- get_vitals_avg_hrv(7d) → "45 ms"
- get_vitals_vo2_max() → "42.5 ml/kg/min"

Datenquellen:
- sleep_log (JSONB segments mit Deep/REM/Light/Awake)
- rest_days (Kraft/Cardio/Entspannung)
- vitals_baseline (resting_hr, hrv, vo2_max)

Jetzt in PLACEHOLDER_MAP registriert → sofort nutzbar.

Fixes: Platzhalter-Export zeigt jetzt alle Werte (statt "nicht verfügbar")

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/placeholder_resolver.py

@@ -290,6 +290,138 @@ def get_trainingstyp_verteilung(profile_id: str, days: int = 14) -> str:
         return ", ".join(parts)
 
 
+def get_sleep_avg_duration(profile_id: str, days: int = 7) -> str:
+    """Calculate average sleep duration in hours."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
+        cur.execute(
+            """SELECT sleep_segments FROM sleep_log
+               WHERE profile_id=%s AND date >= %s
+               ORDER BY date DESC""",
+            (profile_id, cutoff)
+        )
+        rows = cur.fetchall()
+
+        if not rows:
+            return "nicht verfügbar"
+
+        total_minutes = 0
+        for row in rows:
+            segments = row['sleep_segments']
+            if segments:
+                # Sum duration_min from all segments
+                for seg in segments:
+                    total_minutes += seg.get('duration_min', 0)
+
+        if total_minutes == 0:
+            return "nicht verfügbar"
+
+        avg_hours = total_minutes / len(rows) / 60
+        return f"{avg_hours:.1f}h"
+
+
+def get_sleep_avg_quality(profile_id: str, days: int = 7) -> str:
+    """Calculate average sleep quality (Deep+REM %)."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
+        cur.execute(
+            """SELECT sleep_segments FROM sleep_log
+               WHERE profile_id=%s AND date >= %s
+               ORDER BY date DESC""",
+            (profile_id, cutoff)
+        )
+        rows = cur.fetchall()
+
+        if not rows:
+            return "nicht verfügbar"
+
+        total_quality = 0
+        count = 0
+        for row in rows:
+            segments = row['sleep_segments']
+            if segments:
+                deep_rem_min = sum(s.get('duration_min', 0) for s in segments if s.get('stage') in ['Deep', 'REM'])
+                total_min = sum(s.get('duration_min', 0) for s in segments)
+                if total_min > 0:
+                    quality_pct = (deep_rem_min / total_min) * 100
+                    total_quality += quality_pct
+                    count += 1
+
+        if count == 0:
+            return "nicht verfügbar"
+
+        avg_quality = total_quality / count
+        return f"{avg_quality:.0f}% (Deep+REM)"
+
+
+def get_rest_days_count(profile_id: str, days: int = 30) -> str:
+    """Count rest days in the given period."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
+        cur.execute(
+            """SELECT COUNT(DISTINCT date) as count FROM rest_days
+               WHERE profile_id=%s AND date >= %s""",
+            (profile_id, cutoff)
+        )
+        row = cur.fetchone()
+        count = row['count'] if row else 0
+        return f"{count} Ruhetage"
+
+
+def get_vitals_avg_hr(profile_id: str, days: int = 7) -> str:
+    """Calculate average resting heart rate."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
+        cur.execute(
+            """SELECT AVG(resting_hr) as avg FROM vitals_baseline
+               WHERE profile_id=%s AND date >= %s AND resting_hr IS NOT NULL""",
+            (profile_id, cutoff)
+        )
+        row = cur.fetchone()
+
+        if row and row['avg']:
+            return f"{int(row['avg'])} bpm"
+        return "nicht verfügbar"
+
+
+def get_vitals_avg_hrv(profile_id: str, days: int = 7) -> str:
+    """Calculate average heart rate variability."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cutoff = (datetime.now() - timedelta(days=days)).strftime('%Y-%m-%d')
+        cur.execute(
+            """SELECT AVG(hrv) as avg FROM vitals_baseline
+               WHERE profile_id=%s AND date >= %s AND hrv IS NOT NULL""",
+            (profile_id, cutoff)
+        )
+        row = cur.fetchone()
+
+        if row and row['avg']:
+            return f"{int(row['avg'])} ms"
+        return "nicht verfügbar"
+
+
+def get_vitals_vo2_max(profile_id: str) -> str:
+    """Get latest VO2 Max value."""
+    with get_db() as conn:
+        cur = get_cursor(conn)
+        cur.execute(
+            """SELECT vo2_max FROM vitals_baseline
+               WHERE profile_id=%s AND vo2_max IS NOT NULL
+               ORDER BY date DESC LIMIT 1""",
+            (profile_id,)
+        )
+        row = cur.fetchone()
+
+        if row and row['vo2_max']:
+            return f"{row['vo2_max']:.1f} ml/kg/min"
+        return "nicht verfügbar"
+
+
 # ── Placeholder Registry ──────────────────────────────────────────────────────
 
 PLACEHOLDER_MAP: Dict[str, Callable[[str], str]] = {
@@ -323,6 +455,16 @@ PLACEHOLDER_MAP: Dict[str, Callable[[str], str]] = {
     '{{activity_detail}}': get_activity_detail,
     '{{trainingstyp_verteilung}}': get_trainingstyp_verteilung,
 
+    # Schlaf & Erholung
+    '{{sleep_avg_duration}}': lambda pid: get_sleep_avg_duration(pid, 7),
+    '{{sleep_avg_quality}}': lambda pid: get_sleep_avg_quality(pid, 7),
+    '{{rest_days_count}}': lambda pid: get_rest_days_count(pid, 30),
+
+    # Vitalwerte
+    '{{vitals_avg_hr}}': lambda pid: get_vitals_avg_hr(pid, 7),
+    '{{vitals_avg_hrv}}': lambda pid: get_vitals_avg_hrv(pid, 7),
+    '{{vitals_vo2_max}}': get_vitals_vo2_max,
+
     # Zeitraum
     '{{datum_heute}}': lambda pid: datetime.now().strftime('%d.%m.%Y'),
     '{{zeitraum_7d}}': lambda pid: 'letzte 7 Tage',