refactor(scenarios): split monolithic configuration into individual files

- Split `scenarios/scenarios.json` into individual JSON files under `scenarios/data/` named `<scenario-id>.json`
- Split `scenarios/bundles.json` into individual JSON files under `scenarios/bundles/` named `<bundle-id>.json`
- Updated `backend/server.js` to dynamically load scenario and bundle files from their respective directories
- Updated documentation in `scenarios/SCHEMA.md` and `README.md` to reflect the new repository layout and contributor workflow

Signed-off-by: Abhinav Sinha <[email protected]>

scenarios/data/cks-immutable-secret.json

@@ -0,0 +1,33 @@
+{
+  "id": "cks-immutable-secret",
+  "title": "Immutable Secrets",
+  "category": "Cluster Security",
+  "difficulty": "Easy",
+  "type": "task",
+  "weight": 3,
+  "description": "## Immutable Resources\n\nMarking a Secret or ConfigMap as immutable protects it from accidental or malicious modifications, and also improves the performance of the kube-apiserver by significantly decreasing load.\n\n**Your task:**\n\nCreate a Secret named `db-creds` with the key `password` and value `super-secret`. Make this secret **immutable**.\n\n```bash\n# Verify immutability:\nkubectl get secret db-creds -o yaml\n```",
+  "hints": [
+    {
+      "title": "immutable: true",
+      "body": "Set `immutable: true` at the root level of the Secret manifest.",
+      "command": "cat <<EOF | kubectl apply -f -\napiVersion: v1\nkind: Secret\nmetadata:\n  name: db-creds\nimmutable: true\nstringData:\n  password: super-secret\nEOF"
+    }
+  ],
+  "setup_commands": [],
+  "validation": {
+    "commands": [
+      {
+        "description": "Secret db-creds exists and is immutable",
+        "command": "kubectl get secret db-creds -o jsonpath='{.immutable}'",
+        "expected_output": "true",
+        "match": "exact"
+      }
+    ]
+  },
+  "default_namespace": "default",
+  "teardown_commands": [
+    {
+      "command": "kubectl delete secret db-creds --ignore-not-found"
+    }
+  ]
+}