feat: Add Hangfire infrastructure with dynamic storage configuration

- Install Hangfire packages (Core, AspNetCore, SqlServer, InMemory)
- Configure Hangfire in Program.cs with boolean InMemory flag from appsettings
- Add Hangfire dashboard at /hangfire route
- Update appsettings.json with Hangfire:InMemory configuration
- Update launchSettings.json with new launch URL
- Remove obsolete Worker.cs background service

ECMJobRunner.WebCron/Properties/launchSettings.json

@@ -13,7 +13,7 @@
       "commandName": "Project",
       "dotnetRunMessages": true,
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "hangfire",
       "applicationUrl": "http://localhost:5271",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
@@ -23,7 +23,7 @@
       "commandName": "Project",
       "dotnetRunMessages": true,
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "hangfire",
       "applicationUrl": "https://localhost:7027;http://localhost:5271",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
@@ -32,7 +32,7 @@
     "IIS Express": {
       "commandName": "IISExpress",
       "launchBrowser": true,
-      "launchUrl": "swagger",
+      "launchUrl": "hangfire",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
       }