Add grid agent milestone acceptance gate (#135)

config/grid-agent-acceptance-evidence.schema.json

@@ -0,0 +1,28 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://metacrate.invalid/schema/grid-agent-acceptance-v1.json",
+  "title": "MetaCrate grid-agent acceptance evidence",
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["schema_version", "sequence", "unix_millis", "package_version", "source_revision", "rust_toolchain", "command", "profile", "grid_type", "endpoint_capabilities", "stage", "status", "duration_millis", "outcome_code", "evidence_sha256", "metrics", "limitations"],
+  "properties": {
+    "schema_version": { "const": 1 },
+    "sequence": { "type": "integer", "minimum": 1 },
+    "unix_millis": { "type": "integer", "minimum": 0 },
+    "package_version": { "type": "string", "maxLength": 64 },
+    "source_revision": { "type": "string", "maxLength": 96 },
+    "rust_toolchain": { "type": "string", "maxLength": 96 },
+    "command": { "type": "string", "maxLength": 256 },
+    "profile": { "enum": ["deterministic_offline", "live_grid"] },
+    "grid_type": { "type": "string", "maxLength": 96 },
+    "endpoint_capabilities": { "type": "array", "maxItems": 16, "items": { "type": "string", "maxLength": 96 } },
+    "stage": { "type": "string", "maxLength": 96 },
+    "status": { "enum": ["passed", "failed", "not_run"] },
+    "duration_millis": { "type": "integer", "minimum": 0 },
+    "budget_millis": { "type": ["integer", "null"], "minimum": 0 },
+    "outcome_code": { "type": "string", "maxLength": 96 },
+    "evidence_sha256": { "type": "string", "pattern": "^[0-9a-f]{64}$" },
+    "metrics": { "type": "object", "additionalProperties": { "type": ["integer", "number", "boolean", "string"] } },
+    "limitations": { "type": "array", "maxItems": 32, "items": { "type": "string", "maxLength": 256 } }
+  }
+}