feat: Initialize Zastava Webhook service with TLS and Authority authentication

- Added Program.cs to set up the web application with Serilog for logging, health check endpoints, and a placeholder admission endpoint.
- Configured Kestrel server to use TLS 1.3 and handle client certificates appropriately.
- Created StellaOps.Zastava.Webhook.csproj with necessary dependencies including Serilog and Polly.
- Documented tasks in TASKS.md for the Zastava Webhook project, outlining current work and exit criteria for each task.

src/StellaOps.Scanner.WebService/Options/ScannerWebServiceOptions.cs

@@ -60,6 +60,11 @@ public sealed class ScannerWebServiceOptions
     /// </summary>
     public ApiOptions Api { get; set; } = new();
 
+    /// <summary>
+    /// Platform event emission settings.
+    /// </summary>
+    public EventsOptions Events { get; set; } = new();
+
     public sealed class StorageOptions
     {
         public string Driver { get; set; } = "mongo";
@@ -214,6 +219,8 @@ public sealed class ScannerWebServiceOptions
 
         public string Algorithm { get; set; } = "ed25519";
 
+        public string? Provider { get; set; }
+
         public string? KeyPem { get; set; }
 
         public string? KeyPemFile { get; set; }
@@ -236,5 +243,24 @@ public sealed class ScannerWebServiceOptions
         public string ScansSegment { get; set; } = "scans";
 
         public string ReportsSegment { get; set; } = "reports";
+
+        public string PolicySegment { get; set; } = "policy";
+    }
+
+    public sealed class EventsOptions
+    {
+        public bool Enabled { get; set; }
+
+        public string Driver { get; set; } = "redis";
+
+        public string Dsn { get; set; } = string.Empty;
+
+        public string Stream { get; set; } = "stella.events";
+
+        public double PublishTimeoutSeconds { get; set; } = 5;
+
+        public long MaxStreamLength { get; set; } = 10000;
+
+        public IDictionary<string, string> DriverSettings { get; set; } = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
     }
 }