chore: import upstream snapshot with attribution

external_plugins/github/.claude-plugin/plugin.json

@@ -0,0 +1,7 @@
+{
+  "name": "github",
+  "description": "Official GitHub MCP server for repository management. Create issues, manage pull requests, review code, search repositories, and interact with GitHub's full API directly from Claude Code.",
+  "author": {
+    "name": "GitHub"
+  }
+}

external_plugins/github/.mcp.json

@@ -0,0 +1,9 @@
+{
+  "github": {
+    "type": "http",
+    "url": "https://api.githubcopilot.com/mcp/",
+    "headers": {
+      "Authorization": "Bearer ${GITHUB_PERSONAL_ACCESS_TOKEN}"
+    }
+  }
+}