quill: add JSON Schema draft for GET /health response

wizard-work/quill/health-response-schema.json

@@ -0,0 +1,38 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "Health Check Response",
+  "description": "Contract draft for GET /health responses.",
+  "type": "object",
+  "required": ["status", "version", "uptime_seconds"],
+  "properties": {
+    "status": {
+      "type": "string",
+      "enum": ["ok", "degraded", "down"]
+    },
+    "version": {
+      "type": "string",
+      "pattern": "^\\d+\\.\\d+\\.\\d+$"
+    },
+    "uptime_seconds": {
+      "type": "integer",
+      "minimum": 0
+    },
+    "checks": {
+      "type": "object",
+      "additionalProperties": {
+        "type": "object",
+        "required": ["status"],
+        "properties": {
+          "status": {
+            "type": "string",
+            "enum": ["pass", "fail", "warn"]
+          },
+          "latency_ms": {
+            "type": "number",
+            "minimum": 0
+          }
+        }
+      }
+    }
+  }
+}