Defers the onboarding usage survey to the instance's first successful processing (the worker writes a one-time onboarding.firstProcessedAt marker and the overlay gates on it), so it reaches engaged users instead of first-landing visitors.
Replaces the two questions telemetry already answers (modality preference from tool_used, install method from instance_started) with what it can't infer: prior tool, self-host motivation, and discovery source.
Adds feedback_prompt_shown and feedback_prompt_dismissed on all five feedback surfaces (usage survey, per-job prompt, admin install card, global nav dialog, search-miss) so skip and completion rates are measurable, not just submissions. New survey strings translated into all 20 non-English locales.
