Retire or intentionally restore the standard-journeys documentation pipeline

## Problem

The repository retains standard-journey data, generation code, and generated outputs from an earlier documentation structure, but the adopter-facing site no longer has an intentional consumer for them. This increases maintenance and review cost and makes it easy to accidentally republish maintainer-oriented assurance pages.

## Decision required

Choose one outcome:

1. Remove the unused generator, data, checks, and generated outputs, preserving only evidence that has an active release or audit consumer; or
2. Define a deliberate machine-readable consumer and restore the pipeline with clear ownership and publication boundaries.

Do not restore the old Journeys navigation tree as the default adopter experience.

## Acceptance criteria

- [ ] Every retained generated artifact has a named consumer and owner.
- [ ] Dead generation steps and CI checks are removed if no consumer exists.
- [ ] Adopter navigation remains task-oriented and excludes internal assurance terminology.
- [ ] Any retained evidence pages are clearly separated from released beginner documentation.
- [ ] Release and docs checks fail if an unowned generated surface is reintroduced.

Start by inventorying the standard-journey data, generation code, generated outputs, and related release or docs checks named in the issue. Identify every active consumer and owner, then determine whether removal or an intentionally restored machine-readable pipeline is justified. Done means retained artifacts have owners, dead steps are removed, adopter navigation stays task-oriented, and checks prevent unowned surfaces from returning.

Written by the indexing model from the issue text.