fix(mcp): restore legacy SDK compatibility (#39373)

packages/opencode/package.json

@@ -30,7 +30,6 @@
   },
   "devDependencies": {
     "@babel/core": "7.28.4",
-    "@modelcontextprotocol/server": "2.0.0",
     "@octokit/webhooks-types": "7.6.1",
     "@opencode-ai/core": "workspace:*",
     "@opencode-ai/http-recorder": "workspace:*",
@@ -81,7 +80,7 @@
     "@effect/platform-node": "catalog:",
     "@ff-labs/fff-bun": "0.9.4",
     "@gitlab/opencode-gitlab-auth": "1.3.3",
-    "@modelcontextprotocol/client": "2.0.0",
+    "@modelcontextprotocol/sdk": "1.29.0",
     "@octokit/graphql": "9.0.2",
     "@octokit/rest": "catalog:",
     "@openauthjs/openauth": "catalog:",