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.

.gitea/workflows/docs.yml

@@ -49,9 +49,19 @@ jobs:
 
       - name: Validate event schemas
         run: |
+          set -euo pipefail
           for schema in docs/events/*.json; do
             npx ajv compile -c ajv-formats -s "$schema"
           done
+          for sample in docs/events/samples/*.json; do
+            schema_name=$(basename "$sample" .sample.json)
+            schema_path="docs/events/${schema_name}.json"
+            if [ ! -f "$schema_path" ]; then
+              echo "Missing schema for sample ${sample}" >&2
+              exit 1
+            fi
+            npx ajv validate -c ajv-formats -s "$schema_path" -d "$sample"
+          done
 
       - name: Setup Python
         uses: actions/setup-python@v5