Mm 67896 manual cherry pick onto release 10.11 (#35989)

* improves time limit checks

* consistently check for presence of patch fields

* fix variable shadowing in test

* allow idempotent pinning operations with time limit expired

* new utility function for post limit time check

* fix style issue

* Add missing E2E CI files and delivery-platform migration for release-10.11

- Add calculate-playwright-results and calculate-cypress-results GitHub Actions
  (referenced by e2e-tests-playwright-template.yml and e2e-tests-cypress-template.yml
  but never backported to release-10.11)
- Add e2e-tests/playwright/merge.config.mjs (required by merge-reports step)
- Add run-specs Makefile target and server.run_specs.sh (required by run-failed-tests job)
- Fix merge-shard-results step: pin @playwright/test version and add fallback
  for when no blob reports exist (json reporter output used directly)
- Remove pull_request trigger from e2e-tests-ci.yml (delivery-platform migration)
- Remove dead e2e-fulltests-ci.yml and e2e-tests-ci-template.yml

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: yasserfaraazkhan <attitude3cena.yf@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/e2e-tests-ci.yml

@@ -1,11 +1,6 @@
 ---
 name: E2E Tests (pull request)
 on:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
   # Argo Events Trigger (automated):
   #   - Triggered by: Enterprise CI/docker-image status check (success)
   #   - Payload: { ref: "<branch>", inputs: { commit_sha: "<sha>" } }