feat: make each plugin an npm workspace built by a termix-plugin CLI

packages/plugin-sdk/cli/index.mjs

@@ -0,0 +1,43 @@
+#!/usr/bin/env node
+/**
+ * termix-plugin: build, validate, test and pack a Termix plugin.
+ *
+ * Run from a plugin directory (npm run build inside plugins/<id>/ does).
+ */
+
+import process from "node:process";
+import { build } from "./commands/build.mjs";
+import { validate } from "./commands/validate.mjs";
+import { test } from "./commands/test.mjs";
+import { pack } from "./commands/pack.mjs";
+
+const COMMANDS = { build, validate, test, pack };
+
+const [command, ...args] = process.argv.slice(2);
+
+if (!command || command === "--help" || command === "-h") {
+  console.log(
+    [
+      "Usage: termix-plugin <command>",
+      "",
+      "  build      Bundle the plugin into dist/",
+      "  validate   Check manifest.json and the files it names",
+      "  test       Run the plugin's vitest suite",
+      "  pack       Write a .tgz of the built plugin",
+    ].join("\n"),
+  );
+  process.exit(command ? 0 : 1);
+}
+
+const run = COMMANDS[command];
+if (!run) {
+  console.error(`Unknown command: ${command}`);
+  process.exit(1);
+}
+
+try {
+  await run({ cwd: process.cwd(), args });
+} catch (error) {
+  console.error(error?.message ?? error);
+  process.exit(1);
+}