Add plugin framework and settings UI

packages/plugins/sdk/src/dev-cli.ts

@@ -0,0 +1,54 @@
+#!/usr/bin/env node
+import path from "node:path";
+import { startPluginDevServer } from "./dev-server.js";
+
+function parseArg(flag: string): string | undefined {
+  const index = process.argv.indexOf(flag);
+  if (index < 0) return undefined;
+  return process.argv[index + 1];
+}
+
+/**
+ * CLI entrypoint for the local plugin UI preview server.
+ *
+ * This is intentionally minimal and delegates all serving behavior to
+ * `startPluginDevServer` so tests and programmatic usage share one path.
+ */
+async function main() {
+  const rootDir = parseArg("--root") ?? process.cwd();
+  const uiDir = parseArg("--ui-dir") ?? "dist/ui";
+  const host = parseArg("--host") ?? "127.0.0.1";
+  const rawPort = parseArg("--port") ?? "4177";
+  const port = Number.parseInt(rawPort, 10);
+  if (!Number.isFinite(port) || port <= 0 || port > 65535) {
+    throw new Error(`Invalid --port value: ${rawPort}`);
+  }
+
+  const server = await startPluginDevServer({
+    rootDir: path.resolve(rootDir),
+    uiDir,
+    host,
+    port,
+  });
+
+  // eslint-disable-next-line no-console
+  console.log(`Paperclip plugin dev server listening at ${server.url}`);
+
+  const shutdown = async () => {
+    await server.close();
+    process.exit(0);
+  };
+
+  process.on("SIGINT", () => {
+    void shutdown();
+  });
+  process.on("SIGTERM", () => {
+    void shutdown();
+  });
+}
+
+void main().catch((error) => {
+  // eslint-disable-next-line no-console
+  console.error(error instanceof Error ? error.message : String(error));
+  process.exit(1);
+});