test(e2e): unify E2E CI command and align preview URL encoding (#719)

* test(e2e): follow-up fixes for post-merge copilot review feedback

* test(e2e): guard E2E_MAX_PREVIEW_MS against sub-second values

* test(e2e): align preview URL encoding and docs

tests/e2e/README.md

@@ -12,6 +12,7 @@ This folder contains a first MVP of end-to-end automated tests.
   - `/onlinePreview`
   - `/getCorsFile`
 - Basic performance smoke checks (configurable threshold): txt/docx/xlsx preview response time
+- CI combined run command available via `npm run test:ci`
 
 ## Local run
 

tests/e2e/specs/preview-smoke.spec.ts

@@ -7,7 +7,7 @@ function b64(v: string): string {
 }
 
 async function openPreview(request: any, fileUrl: string) {
-  const encoded = b64(fileUrl);
+  const encoded = encodeURIComponent(b64(fileUrl));
   return request.get(`/onlinePreview?url=${encoded}`);
 }