feat: Add organization name and scheduler refresh interval settings

- Superadmin-only organization name setting displayed in dashboard header
- Advanced Options tab with configurable scheduler refresh interval (0 = disabled)
- Make system settings GET endpoint public for frontend reads
- Scheduler reads refresh_seconds from DB dynamically each loop
- Seed default system settings in init_defaults.py

scheduler/scheduler.py

@@ -2,7 +2,7 @@
 
 import os
 import logging
-from .db_utils import get_active_events
+from .db_utils import get_active_events, get_system_setting_value
 import paho.mqtt.client as mqtt
 import json
 import datetime
@@ -37,7 +37,12 @@ def main():
 
     POLL_INTERVAL = 30  # Sekunden, Empfehlung für seltene Änderungen
     # 0 = aus; z.B. 600 für alle 10 Min
-    REFRESH_SECONDS = int(os.getenv("REFRESH_SECONDS", "0"))
+    # initial value from DB or fallback to env
+    try:
+        db_val = get_system_setting_value("refresh_seconds", None)
+        REFRESH_SECONDS = int(db_val) if db_val is not None else int(os.getenv("REFRESH_SECONDS", "0"))
+    except Exception:
+        REFRESH_SECONDS = int(os.getenv("REFRESH_SECONDS", "0"))
     # Konfigurierbares Zeitfenster in Tagen (Standard: 7)
     WINDOW_DAYS = int(os.getenv("EVENTS_WINDOW_DAYS", "7"))
     last_payloads = {}       # group_id -> payload
@@ -58,6 +63,12 @@ def main():
 
     while True:
         now = datetime.datetime.now(datetime.timezone.utc)
+        # refresh interval can change at runtime (superadmin settings)
+        try:
+            db_val = get_system_setting_value("refresh_seconds", None)
+            REFRESH_SECONDS = int(db_val) if db_val is not None else REFRESH_SECONDS
+        except Exception:
+            pass
         # Query window: next N days to capture upcoming events and recurring instances
         # Clients need to know what's coming, not just what's active right now
         end_window = now + datetime.timedelta(days=WINDOW_DAYS)