Add shared port registry workflow and improve scaffold tooling

install/merge-managed-mcp-config.test.mjs

@@ -203,6 +203,25 @@ test("preserves comments and custom servers while pruning stale managed MCP entr
   assert.equal(parsed.servers.gitea, undefined);
 });
 
+test("creates managed MCP config from an empty target file", () => {
+  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "copilot-mcp-"));
+  const targetFile = path.join(tempDir, "mcp.json");
+
+  fs.writeFileSync(targetFile, "", "utf8");
+
+  const result = runMerge({
+    targetFile,
+    templateFile: vscodeTemplateFile,
+    serverKey: "servers",
+  });
+  assert.equal(result.status, 0, result.stderr);
+
+  const output = fs.readFileSync(targetFile, "utf8");
+  const parsed = parseJsonc(output);
+  assert.equal(parsed.servers.playwright.command, "npx");
+  assert.equal(parsed.servers.filesystem.command, "docker");
+});
+
 test("renders optional Gitea config when local overrides are complete", () => {
   const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "copilot-mcp-"));
   const targetFile = path.join(tempDir, "mcp-config.json");