test(playground): read the repository's policy file in the engine test

The examples test read public/playground/sqlquack.toml, which only the
site build copies there, and CI tests the engine before it builds the
site. It now reads sqlquack.toml at the repository root, as the other
tests in the file do.

Author: kvlonge

website/tests/playground.test.mjs

@@ -102,7 +102,8 @@ test('every example stops at the stage it is meant to, under the default policy
 	};
 	assert.deepEqual(Object.keys(EXAMPLES).sort(), Object.keys(expected).sort());
 	// The page starts on the repository's policy under a UTC session; its switch turns to strict.
-	const policy = readFileSync(new URL('../public/playground/sqlquack.toml', import.meta.url), 'utf8');
+	// The repository's policy file, which the build copies to public/playground/ for the page.
+	const policy = readFileSync(new URL('../../sqlquack.toml', import.meta.url), 'utf8');
 	const modes = { repository: JSON.stringify({ policy, utc_session: true }), strict: undefined };
 	for (const [mode, settings] of Object.entries(modes)) {
 		for (const [name, sql] of Object.entries(EXAMPLES)) {