Initial scaffold: skill definitions and subtask schemas

Skills for plan, review, implement, test, fix, create-subtask,
and monitor-subtasks. Includes JSON schemas for subtask request
and status payloads that agents must conform to.

schemas/subtask-status.json

@@ -0,0 +1,41 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "title": "SubtaskStatus",
+  "description": "Schema for the response when querying a subtask's status",
+  "type": "object",
+  "properties": {
+    "id": {
+      "type": "string",
+      "format": "uuid"
+    },
+    "command": {
+      "type": "string"
+    },
+    "repository": {
+      "type": "string"
+    },
+    "status": {
+      "type": "string",
+      "enum": ["pending", "running", "succeeded", "failed", "cancelled"]
+    },
+    "result": {
+      "type": "string",
+      "description": "Output from the completed subtask"
+    },
+    "errorMessage": {
+      "type": "string"
+    },
+    "createdAt": {
+      "type": "string",
+      "format": "date-time"
+    },
+    "startedAt": {
+      "type": ["string", "null"],
+      "format": "date-time"
+    },
+    "completedAt": {
+      "type": ["string", "null"],
+      "format": "date-time"
+    }
+  }
+}