- Move useTranslateSession() to TranslatorPageClient (shell level) for PipelineView to receive real steps
- Build PipelineStep[] from session result (detected/intermediate/translated/response)
- Pass session as prop down to TranslateTab; internal hook kept for isolated test compatibility
- Dedup useProviderOptions: only TranslateTab calls the hook, props pass to SimpleControls
- Remove unused data-advanced-section/data-input-text placeholder (DOM data leak GAP-5)
- Add aria-expanded + aria-controls to AutoFeaturesCard toggle (a11y GAP-2)
Addresses code review RISCO-4, GAP-2, GAP-3, GAP-5.
