Uncommitted sx-tools changes: WASM bundles, Playwright specs, engine fixes

WASM browser bundles rebuilt with latest kernel. Playwright test specs
updated (helpers, navigation, handler-responses, hypermedia-handlers,
isomorphic, SPA navigation). Engine/boot/orchestration SX files updated.
Handler examples and not-found page refreshed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/playwright/handler-responses.spec.js

@@ -69,7 +69,7 @@ test.describe('Handler responses render correctly', () => {
     await loadPage(page, '(geography.(hypermedia.(example.active-search)))');
 
     const input = page.locator('input[placeholder*="earch"], input[name="q"]').first();
-    await input.fill('python');
+    await input.pressSequentially('python', { delay: 50 });
     await page.waitForTimeout(2000);
 
     const results = page.locator('#search-results');