feat: Add Serilog SQLite sink and Serilog.UI dashboard with centralized log directory configuration

- Add Serilog.Sinks.SQLite v7.0.0 for structured logging to SQLite database
- Add Serilog.UI v3.2.0 and Serilog.UI.SqliteProvider v1.1.0 for web-based log viewer
- Add Serilog.Settings.Configuration v10.0.1 for configuration support
- Configure SQLite log storage at E:\LogFiles\Digital Data\ECMJobRunner.WebCron\logs.db
- Add Serilog.UI dashboard at /serilog-ui endpoint
- Centralize log directory configuration in appsettings.json (Logging:LogDirectory)
- Configure Serilog programmatically with Console and SQLite sinks
- Remove deprecated Serilog configuration from appsettings files (now using code-based config)
- Enable Serilog self-diagnostics for troubleshooting
- Both Serilog sink and Serilog.UI use same SQLite database path from configuration

ECMJobRunner.WebCron/appsettings.Development.json

@@ -1,22 +1,10 @@
 {
-  "Serilog": {
-    "Using": [ "Serilog.Sinks.Console" ],
-    "MinimumLevel": {
+  "Logging": {
+    "LogLevel": {
       "Default": "Debug",
-      "Override": {
-        "Microsoft.AspNetCore": "Warning",
-        "Microsoft.EntityFrameworkCore": "Warning",
-        "Hangfire": "Information"
-      }
-    },
-    "WriteTo": [
-      {
-        "Name": "Console",
-        "Args": {
-          "outputTemplate": "[{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}"
-        }
-      }
-    ],
-    "Enrich": [ "FromLogContext", "WithMachineName", "WithThreadId" ]
+      "Microsoft.AspNetCore": "Warning",
+      "Microsoft.EntityFrameworkCore": "Warning",
+      "Hangfire": "Information"
+    }
   }
 }