test(webui): add comprehensive unit test suite (#1738)

test(webui): add comprehensive unit test suite (#1738)

* test(webui): add test infrastructure and setup

* test(webui): add Utils composable tests

* test(webui): refactor and expand UIClient tests

* test(webui): add action modal component tests

* test(webui): fix JSDoc warnings in mount factory functions

* test(webui): add ChargingStationsView tests

* [autofix.ci] apply automated fixes

* test(webui): finalize coverage and verify quality gates

* test(webui): harmonize test infrastructure — extract ButtonStub, unify toast mock, DRY error tests

* test(webui): add missing coverage for timeout, server switching, authorize errors, WS states

* test(webui): raise coverage thresholds to match achieved 93%/91%/85%/93%

* test(webui): address PR review — unify mock cleanup, improve MockWebSocket fidelity, fix types

* test(webui): adapt tests for new OCPP Version column

* test(webui): remove MockWebSocket auto-open, robustify component lookups, add open assertion

* test(webui): init MockWebSocket readyState to CONNECTING per WebSocket spec

* fix(webui): use window.localStorage for Node 22+ jsdom compatibility

* fix(webui): disable Node 25+ native webstorage to prevent jsdom localStorage conflict

* test(webui): await router.isReady() in App mount test

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Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>