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.

samples/api/scheduler/audit.json

@@ -0,0 +1,19 @@
+{
+  "id": "audit_169754",
+  "tenantId": "tenant-alpha",
+  "category": "scheduler",
+  "action": "pause",
+  "occurredAt": "2025-10-18T22:10:00+00:00",
+  "actor": {
+    "actorId": "user_admin",
+    "displayName": "Cluster Admin",
+    "kind": "user"
+  },
+  "scheduleId": "sch_20251018a",
+  "correlationId": "corr-123",
+  "metadata": {
+    "details": "schedule paused",
+    "reason": "maintenance"
+  },
+  "message": "Paused via API"
+}