Packaging, rtut check, tests CI job; schemas move into the package (RBT-WP-0009-T02)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: sonnet
Assistant-Process: 295952@bnt-lap001
Assistant-Session: e93f64ad-516c-46eb-9666-aad8d300c477

rtut/schema/attribute-set.schema.json

@@ -0,0 +1,37 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://runbook-tutorials.invalid/schema/attribute-set/v0.1",
+  "title": "Attribute set",
+  "type": "object",
+  "required": ["spec", "id", "title", "attributes"],
+  "additionalProperties": false,
+  "properties": {
+    "spec": {"const": "attribute-set/v0.1"},
+    "id": {"type": "string", "pattern": "^[a-z0-9]+([.-][a-z0-9]+)*$"},
+    "title": {"type": "string", "minLength": 3},
+    "extends": {"type": "array", "items": {"type": "string"}, "description": "Composed first; later entries and this set's own attributes override."},
+    "attributes": {"$ref": "#/$defs/attributes"}
+  },
+  "$defs": {
+    "attributes": {
+      "type": "object",
+      "propertyNames": {"pattern": "^[a-z][a-z0-9_]*$"},
+      "additionalProperties": {"$ref": "#/$defs/attribute"}
+    },
+    "attribute": {
+      "oneOf": [
+        {"type": ["string", "integer", "boolean"]},
+        {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "value": {"type": ["string", "integer", "boolean"]},
+            "requirement": {"enum": ["required", "optional"]},
+            "note": {"type": "string"}
+          },
+          "minProperties": 1
+        }
+      ]
+    }
+  }
+}