Refactor and update various components of EchoHub.Server

- Updated launchSettings.json for consistency.
- Refactored FileValidationHelper to improve image validation logic.
- Enhanced ServerDirectoryService for better connection handling and user count updates.
- Improved DatabaseSetup for legacy database handling and seeding default channels.
- Refined FirstRunSetup to ensure JWT secret generation.
- Removed appsettings.Development.json as it is no longer needed.
- Updated EchoHub.Tests project file for consistency.
- Added unit tests for FileValidationHelper and PresenceTracker with improved assertions.
- Updated ValidationConstantsTests to ensure regex validations are correct.
- Cleaned up solution file formatting for better readability.

src/EchoHub.Server/Properties/launchSettings.json

@@ -1,23 +1,23 @@
-{
-	"$schema": "https://json.schemastore.org/launchsettings.json",
-	"profiles": {
-		"http": {
-			"commandName": "Project",
-			"dotnetRunMessages": true,
-			"launchBrowser": true,
-			"applicationUrl": "http://localhost:5000",
-			"environmentVariables": {
-				"ASPNETCORE_ENVIRONMENT": "Development"
-			}
-		},
-		"https": {
-			"commandName": "Project",
-			"dotnetRunMessages": true,
-			"launchBrowser": true,
-			"applicationUrl": "https://localhost:7171;http://localhost:5189",
-			"environmentVariables": {
-				"ASPNETCORE_ENVIRONMENT": "Development"
-			}
-		}
-	}
-}
+{
+	"$schema": "https://json.schemastore.org/launchsettings.json",
+	"profiles": {
+		"http": {
+			"commandName": "Project",
+			"dotnetRunMessages": true,
+			"launchBrowser": true,
+			"applicationUrl": "http://localhost:5000",
+			"environmentVariables": {
+				"ASPNETCORE_ENVIRONMENT": "Development"
+			}
+		},
+		"https": {
+			"commandName": "Project",
+			"dotnetRunMessages": true,
+			"launchBrowser": true,
+			"applicationUrl": "https://localhost:7171;http://localhost:5189",
+			"environmentVariables": {
+				"ASPNETCORE_ENVIRONMENT": "Development"
+			}
+		}
+	}
+}