wwtest: native package-test coordinator

Single-directory package-test planner: discovers *.ww, groups white-box
and external <pkg>_test sources, composes the combined test package,
builds it through the sibling ww driver, and runs it with the runtime's
-package/-list/-timeout-ms contract. test/package holds its E2E corpus
and the manual runtime fixture set.

cmd/wwtest/wwtest.ww

@@ -0,0 +1,14 @@
+package main;
+
+import os;
+import wwpackage;
+
+export fn main() int = {
+	let args: []str = os.args();
+	if (args.len < 2 || args[1] != "package") {
+		let usage: str = "usage: wwtest package [options] [DIR]\n";
+		os.write(os.STDERR_FILENO, usage.ptr, usage.len: u64);
+		return 2;
+	};
+	return wwpackage.packagecommand(args[2:args.len]);
+};