chore(opencode-sandbox): add SSH config, git safe directory, and test setup

.opencode-sandbox/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "opencode-sandbox",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "test:coverage": "jest --coverage"
+  },
+  "devDependencies": {
+    "@types/jest": "29.5.12",
+    "@types/node": "20.11.0",
+    "jest": "29.7.0",
+    "ts-jest": "29.1.2",
+    "typescript": "5.3.3"
+  }
+}