Track e2e test pass/fail status per WebUI release version

## Background

WebUI e2e tests currently run best-effort against the `main` branch only (main-branch WebUI vs main-branch backend, with auto-heal PRs for broken tests). There is no tag or record indicating which e2e tests actually pass for a given released WebUI version (e.g. 26.4.9).

Downstream QA / installation-verification automation (Playwright-container-based post-install UI testing) wants to reuse the WebUI e2e suite against a specific released version, but without per-release pass/fail information they must re-verify every test themselves — the suite cannot be trusted as-is for any tagged version.

## Proposal

At release time, record which e2e tests pass and which fail for that release, and make this queryable/consumable. For example:

- Publish e2e test results (pass/fail list) alongside each release tag
- Allow consumers to run only the tests that passed (or re-check the ones that failed) at that release point

## Notes

- No code-freeze stage exists today, so guaranteeing 100% green e2e at release is out of scope; the goal is **transparency of test status per release**, not a green guarantee.
- Docs are already managed per version; e2e is main-branch-only — this issue bridges that gap for e2e.

—

Captured while working on branch: feat/FR-3376-check2-backlog

JIRA Issue: FR-3382

Start by locating the WebUI e2e test runner, release workflow, and the Playwright-container-based post-install testing entry point. Trace how tests run against main and how release tags are published; done means each release exposes a consumable pass/fail result and downstream automation can select passed or failed tests for that version.

Written by the indexing model from the issue text.