fix: ensure lib is built before examples:build (#185)

* fix: ensure lib is built before examples:build

Add preexamples:build hook to automatically run `npm run build` before
`examples:build`. This ensures examples always type-check against the
latest library code, catching breaking changes during development.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* feat: add version consistency check for examples

Add scripts/check-versions.mjs to verify that example package.json files
reference the correct version of @modelcontextprotocol/ext-apps.

- Allows "../.." (local dev) or "^{root-version}" as valid dependencies
- Runs in CI before npm install to catch mismatches early
- Available locally via `npm run check:versions`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: regenerate package-lock.json for cross-platform compatibility

---------

Co-authored-by: Claude <noreply@anthropic.com>

scripts/check-versions.mjs

@@ -0,0 +1,49 @@
+#!/usr/bin/env node
+/**
+ * Checks that example package.json files reference the same version
+ * of @modelcontextprotocol/ext-apps as the root package.json.
+ *
+ * This ensures examples stay in sync with the library version.
+ */
+
+import { readFileSync, readdirSync, statSync, existsSync } from "fs";
+import { join } from "path";
+
+const rootPkg = JSON.parse(readFileSync("package.json", "utf-8"));
+const rootVersion = rootPkg.version;
+const pkgName = rootPkg.name;
+
+const expectedDep = `^${rootVersion}`;
+
+let hasError = false;
+
+const examplesDir = "examples";
+const examples = readdirSync(examplesDir).filter((d) => {
+  const pkgPath = join(examplesDir, d, "package.json");
+  return statSync(join(examplesDir, d)).isDirectory() && existsSync(pkgPath);
+});
+
+for (const example of examples) {
+  const pkgPath = join(examplesDir, example, "package.json");
+  const pkg = JSON.parse(readFileSync(pkgPath, "utf-8"));
+
+  const dep = pkg.dependencies?.[pkgName];
+  // Allow "../.." (local dev) or the correct versioned dependency
+  if (dep && dep !== expectedDep && dep !== "../..") {
+    console.error(
+      `❌ ${pkgPath}: expected "${pkgName}": "${expectedDep}" (or "../.."), got "${dep}"`,
+    );
+    hasError = true;
+  }
+}
+
+if (hasError) {
+  console.error(
+    `\nRun the following to fix:\n  npm pkg set dependencies.${pkgName}=${expectedDep} --workspaces`,
+  );
+  process.exit(1);
+} else {
+  console.log(
+    `✅ All examples reference ${pkgName}@${expectedDep} (root version: ${rootVersion})`,
+  );
+}