Add comprehensive validation system with runtime configuration

Implements a flexible validation framework for student rankings, team assignments, and team composition with administrator-configurable rules and thresholds.

Validation System:
- Reflection-based rule discovery eliminates manual registration
- Base classes (RequiredEventTypeRuleBase, EventCountThresholdRuleBase) reduce code duplication by ~250 lines
- 12 validation rules covering event requirements, counts, and team constraints
- Configurable severity levels (Warning/Error) per rule type
- ValidationService with caching for optimal performance
- Rules apply contextually (StudentRanking, StudentAssignment, TeamComposition)

Configuration & Admin UI:
- ValidationSettings admin page for editing thresholds and severity levels
- ChapterSettings admin page for editing chapter information
- Settings stored in Data/appsettings.json for runtime configuration
- JSON config works in both development and production environments
- Auto-creates Data directory and config template on first run

User Experience:
- ValidationWarnings component displays inline warnings/errors
- Integrated in Event Ranking, Registration, and Team Assignment pages
- Color-coded severity indicators (warning yellow, error red)
- Includes "Too Many Regional Events" rule (max 3 recommended)

Technical Improvements:
- Template Method pattern for rule base classes
- Singleton rule instances with lazy initialization
- Configuration loaded via IConfiguration with fallback to defaults
- Safe JSON updates preserve other appsettings sections

WebApp/Program.cs

@@ -11,62 +11,66 @@ using WebApp.Logging;
 
 var builder = WebApplication.CreateBuilder(args);
 
-// Load optional appsettings from Data directory in production (overrides defaults)
-// In development, use appsettings.Development.json instead
-if (builder.Environment.IsProduction())
+// Load appsettings from Data directory (works in both development and production)
+// This allows runtime configuration changes without touching the codebase
+var dataAppSettingsPath = Path.Combine(builder.Environment.ContentRootPath, "Data", "appsettings.json");
+if (!File.Exists(dataAppSettingsPath))
 {
-    var dataAppSettingsPath = Path.Combine(builder.Environment.ContentRootPath, "Data", "appsettings.json");
-    if (!File.Exists(dataAppSettingsPath))
+    Console.WriteLine($"appsettings.json not found at {dataAppSettingsPath}. Creating from template...");
+
+    try
     {
-        Console.WriteLine($"appsettings.json not found at {dataAppSettingsPath}. Creating from template...");
+        // Ensure Data directory exists
+        Directory.CreateDirectory(Path.Combine(builder.Environment.ContentRootPath, "Data"));
 
-        try
+        // Copy ChapterSettings and ValidationSettings from the base appsettings.json
+        var baseAppSettingsPath = Path.Combine(builder.Environment.ContentRootPath, "appsettings.json");
+        if (File.Exists(baseAppSettingsPath))
         {
-            // Ensure Data directory exists
-            Directory.CreateDirectory(Path.Combine(builder.Environment.ContentRootPath, "Data"));
+            var baseConfig = File.ReadAllText(baseAppSettingsPath);
+            var baseDoc = JsonDocument.Parse(baseConfig);
 
-            // Copy ChapterSettings from the base appsettings.json
-            var baseAppSettingsPath = Path.Combine(builder.Environment.ContentRootPath, "appsettings.json");
-            if (File.Exists(baseAppSettingsPath))
+            var templateSettings = new Dictionary<string, object?>();
+
+            if (baseDoc.RootElement.TryGetProperty("ChapterSettings", out var chapterSettings))
             {
-                var baseConfig = File.ReadAllText(baseAppSettingsPath);
-                var baseDoc = JsonDocument.Parse(baseConfig);
+                templateSettings["ChapterSettings"] = JsonSerializer.Deserialize<object>(chapterSettings.GetRawText());
+            }
 
-                if (baseDoc.RootElement.TryGetProperty("ChapterSettings", out var chapterSettings))
+            if (baseDoc.RootElement.TryGetProperty("ValidationSettings", out var validationSettings))
+            {
+                templateSettings["ValidationSettings"] = JsonSerializer.Deserialize<object>(validationSettings.GetRawText());
+            }
+
+            if (templateSettings.Any())
+            {
+                var json = JsonSerializer.Serialize(templateSettings, new JsonSerializerOptions
                 {
-                    var templateSettings = new
-                    {
-                        ChapterSettings = JsonSerializer.Deserialize<object>(chapterSettings.GetRawText())
-                    };
+                    WriteIndented = true
+                });
 
-                    var json = JsonSerializer.Serialize(templateSettings, new JsonSerializerOptions
-                    {
-                        WriteIndented = true
-                    });
-
-                    File.WriteAllText(dataAppSettingsPath, json);
-                    Console.WriteLine("appsettings.json created in Data directory. Please update ChapterSettings with your chapter information.");
-                }
-                else
-                {
-                    Console.WriteLine("WARNING: ChapterSettings not found in base appsettings.json");
-                }
+                File.WriteAllText(dataAppSettingsPath, json);
+                Console.WriteLine("appsettings.json created in Data directory.");
+            }
+            else
+            {
+                Console.WriteLine("WARNING: No settings to copy from base appsettings.json");
             }
         }
-        catch (Exception ex)
-        {
-            Console.WriteLine($"WARNING: Unable to create appsettings.json: {ex.Message}");
-        }
     }
-
-    // Add Data/appsettings.json as additional configuration source
-    if (File.Exists(dataAppSettingsPath))
+    catch (Exception ex)
     {
-        builder.Configuration.AddJsonFile(dataAppSettingsPath, optional: true, reloadOnChange: true);
-        Console.WriteLine($"Loaded configuration from {dataAppSettingsPath}");
+        Console.WriteLine($"WARNING: Unable to create appsettings.json: {ex.Message}");
     }
 }
 
+// Add Data/appsettings.json as additional configuration source (all environments)
+if (File.Exists(dataAppSettingsPath))
+{
+    builder.Configuration.AddJsonFile(dataAppSettingsPath, optional: true, reloadOnChange: true);
+    Console.WriteLine($"Loaded configuration from {dataAppSettingsPath}");
+}
+
 // Configure Serilog with custom handling for antiforgery errors
 builder.Host.UseSerilog((context, configuration) =>
 {
@@ -172,6 +176,15 @@ builder.Services.AddScoped<WebApp.LocalStorageService>();
 // State container for maintaining state per user connection (Blazor Server)
 builder.Services.AddScoped<StateContainer>();
 
+// Load validation configuration from appsettings (or use default if not found)
+var validationConfig = builder.Configuration
+    .GetSection("ValidationSettings")
+    .Get<Core.Validation.ValidationConfiguration>() ?? Core.Validation.ValidationConfiguration.Default;
+
+// Validation service with loaded configuration
+builder.Services.AddScoped<Core.Validation.ValidationService>(sp =>
+    new Core.Validation.ValidationService(validationConfig));
+
 // Add authentication services
 builder.Services.AddHttpContextAccessor();
 builder.Services.AddScoped<AuthenticationService>();