analysis.feature and full-ui-path.feature used [data-e2e=toggle-btn]
(exact match) which no longer works since toggle buttons now have
compound selectors (e.g. "toggle-btn configure-btn"). Switch to
word-match [data-e2e~=configure-btn].
Add dedicated data-e2e selectors (configure-btn, verify-btn, prepare-btn)
to StudioPage toggle buttons and update E2E tests to use waitFor + click
on these selectors instead of locateAll index tricks. Fixes timeout in
rechunk.feature caused by race with async feature flag loading.
Closes#176
