First implementation (#1)

Reviewed-on: #1

schemas/spot-check.schema.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://paperspec.scient.ing/schemas/spot-check.schema.json",
+  "title": "Spot-check seed payload",
+  "description": "scienting-spot-check/1: the payload a spot-check key signs to seed a sample; it names a receipt by its record hash and is never a file of its own; spec/08-fidelity.md §8.8.",
+  "type": "object",
+  "properties": {
+    "format": {
+      "const": "scienting-spot-check/1"
+    },
+    "receipt": {
+      "$ref": "common.schema.json#/$defs/hash"
+    }
+  },
+  "required": [
+    "format",
+    "receipt"
+  ],
+  "additionalProperties": false
+}