fix: agent-08 Kiosk-Härtung + 24h-Zeiteintrag-Bug

- fix: worked_minutes nutzt jetzt Sekunden statt Minuten für Overnight-Vergleich
  (end < start statt end <= start) – verhindert 24h-Anzeige bei Schnell-Stempel
  in derselben Minute (z.B. 23:34:46 → 23:34:48)
- fix: _check_arbzg() gleicher Sec-basierter Fix
- fix: KioskDeviceStatus Enum values_callable → kiosk list crasht nicht mehr
- feat: kiosk rotate-key CLI-Kommando (Status→pending, Re-Enrollment)
- feat: Kiosk-Settings in CompanyOut/CompanyUpdate Schema (require_approval,
  track_current_user, heartbeat_interval_sec)
- feat: Kiosk-Terminal-Einstellungsblock in CompanySettingsPage (🖥️)

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

backend/app/models/kiosk_device.py

@@ -40,7 +40,7 @@ class KioskDevice(Base):
 
     # ── Ed25519-Auth (löst token_hash + is_active ab) ─────────────────────────
     status: Mapped[KioskDeviceStatus] = mapped_column(
-        Enum(KioskDeviceStatus, name="kioskdevicestatus"),
+        Enum(KioskDeviceStatus, name="kioskdevicestatus", values_callable=lambda x: [e.value for e in x]),
         nullable=False,
         default=KioskDeviceStatus.REVOKED,
     )

backend/app/models/time_entry.py

@@ -66,11 +66,18 @@ class TimeEntry(Base):
         """Gearbeitete Minuten (ohne Pausen), None wenn noch offen."""
         if self.end_time is None:
             return None
-        start_total = self.start_time.hour * 60 + self.start_time.minute
-        end_total = self.end_time.hour * 60 + self.end_time.minute
-        if end_total <= start_total:
-            end_total += 24 * 60  # overnight shift
-        return max(0, end_total - start_total - self.break_minutes)
+        # Sekunden einbeziehen um Sub-Minuten-Einträge korrekt zu behandeln
+        # (z.B. Einstemp+Ausstemp in derselben Minute → soll 0h zeigen, nicht 24h)
+        start_secs = (self.start_time.hour * 3600
+                      + self.start_time.minute * 60
+                      + self.start_time.second)
+        end_secs = (self.end_time.hour * 3600
+                    + self.end_time.minute * 60
+                    + self.end_time.second)
+        if end_secs < start_secs:
+            end_secs += 24 * 3600  # Nachtschicht (Ende am nächsten Tag)
+        total_mins = (end_secs - start_secs) // 60
+        return max(0, total_mins - self.break_minutes)
 
     @property
     def worked_hours(self) -> float | None: