feat(dashboard+api): card-based dashboard, camelCase API, UTC fixes

Dashboard: new Syncfusion card layout, global stats, filters, health bars, active event display, client details, bulk restart, 15s auto-refresh, manual refresh toasts
API: standardized responses to camelCase; added serializers.py and updated events endpoints
Time: ensured UTC storage; frontend appends 'Z' for parsing and displays local time
Docs: updated copilot-instructions.md, README.md, TECH-CHANGELOG.md
Program Info: bumped to 2025.1.0-alpha.12 with user-facing changelog
BREAKING: external API consumers must migrate field names from PascalCase to camelCase.

scheduler/scheduler.py

@@ -9,18 +9,19 @@ import datetime
 import time
 
 # Logging-Konfiguration
-ENV = os.getenv("ENV", "development")
-LOG_LEVEL = os.getenv("LOG_LEVEL", "DEBUG" if ENV == "development" else "INFO")
+from logging.handlers import RotatingFileHandler
 LOG_PATH = os.path.join(os.path.dirname(__file__), "scheduler.log")
 os.makedirs(os.path.dirname(LOG_PATH), exist_ok=True)
-log_handlers = []
-if ENV == "production":
-    from logging.handlers import RotatingFileHandler
-    log_handlers.append(RotatingFileHandler(
-        LOG_PATH, maxBytes=2*1024*1024, backupCount=5, encoding="utf-8"))
-else:
-    log_handlers.append(logging.FileHandler(LOG_PATH, encoding="utf-8"))
-if os.getenv("DEBUG_MODE", "1" if ENV == "development" else "0") in ("1", "true", "True"):
+LOG_LEVEL = os.getenv("LOG_LEVEL", "INFO")
+log_handlers = [
+    RotatingFileHandler(
+        LOG_PATH,
+        maxBytes=10*1024*1024,  # 10 MB
+        backupCount=2,          # 1 current + 2 backups = 3 files total
+        encoding="utf-8"
+    )
+]
+if os.getenv("DEBUG_MODE", "0") in ("1", "true", "True"):
     log_handlers.append(logging.StreamHandler())
 logging.basicConfig(
     level=getattr(logging, LOG_LEVEL.upper(), logging.INFO),