Implement SAND-WP-0003: validation meta-framework extraction

Port e2e-framework schema, runner, and reporter into wise-validator with
sand-boxer CLI integration, validate run CLI, unit tests, registry capability,
and operator docs.

tests/fixtures/minimal_repo/docker-compose.yml

@@ -0,0 +1,5 @@
+services:
+  web:
+    image: docker.io/library/nginx:alpine
+    ports:
+      - "127.0.0.1:8080:80"

tests/fixtures/minimal_repo/e2e/e2e.yml

@@ -0,0 +1,9 @@
+name: fixture-repo
+compose_file: docker-compose.yml
+health_checks:
+  - name: web
+    url: http://localhost:8080
+    timeout: 30
+test_command: "echo ok"
+timeout: 60
+cleanup: always