feat: add Claude Code plugin config

.claude-plugin/marketplace.json

@@ -0,0 +1,23 @@
+{
+  "name": "spanner-marketplace",
+  "interface": {
+    "displayName": "Spanner Agent Skills"
+  },
+  "metadata": {
+    "description": "Agent skills to connect and interact with Spanner data using natural language."
+  },
+  "plugins": [
+    {
+      "name": "spanner",
+      "source": {
+        "source": "git",
+        "url": "https://github.com/gemini-cli-extensions/spanner.git"
+      },
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_INSTALL"
+      },
+      "category": "Database"
+    }
+  ]
+}

.claude-plugin/plugin.json

@@ -0,0 +1,39 @@
+{
+  "name": "spanner",
+  "version": "0.2.6",
+  "description": "Connect and interact with Spanner data using natural language.",
+  "author": {
+    "name": "Google LLC",
+    "email": "data-cloud-ai-integrations@google.com"
+  },
+  "homepage": "https://cloud.google.com/spanner",
+  "license": "Apache-2.0",
+  "repository": "https://github.com/gemini-cli-extensions/spanner",
+  "skills": "./skills/",
+  "userConfig": {
+    "spanner_project": {
+      "title": "Project ID",
+      "description": "ID of the Google Cloud project",
+      "type": "string",
+      "sensitive": false
+    },
+    "spanner_instance": {
+      "title": "Instance",
+      "description": "ID of the Spanner instance",
+      "type": "string",
+      "sensitive": false
+    },
+    "spanner_database": {
+      "title": "Database",
+      "description": "ID of the Spanner database",
+      "type": "string",
+      "sensitive": false
+    },
+    "spanner_dialect": {
+      "title": "Database Dialect",
+      "description": "(Optional) The SQL dialect of the Spanner Database: 'googlesql' or 'postgresql'. (Default: 'googlesql')",
+      "type": "string",
+      "sensitive": false
+    }
+  }
+}