Stabilize Playwright phase 8 with page smokes and flake fixes.

Direct-navigate Calibrate, harden stub agent timing, and add Emberwake/Seer/Oath smokes so the full 32-spec E2E sweep passes reliably.

server/web/playwright.config.ts

@@ -4,7 +4,7 @@ export default defineConfig({
   globalTeardown: './e2e/global-teardown.ts',
   testDir: './e2e',
   timeout: 60_000,
-  retries: 0,
+  retries: 1,
   // Live-server specs share one stub agent_id — parallel workers race on WS auth.
   workers: process.env.AETHERFORGE_URL ? 1 : undefined,
   use: {