Replace comment surfaces with an admin ingestion-status skeleton

## Parent PRD

#1

## What to build

Create the first replacement slice for the comment-suggestion removal by removing the old comment feature from the active product surface and landing a minimal admin-only ingestion status skeleton behind the existing Cloudflare Access boundary. This slice should preserve legacy comment data for rollback safety while establishing the new admin destination described in the parent PRD.

## Acceptance criteria

- [ ] The comment suggestion UI, navigation entry points, and active runtime hooks are removed from the product surface without destructively deleting legacy data.
- [ ] Admins can reach a replacement ingestion status page through the existing admin access flow.
- [ ] Public stall browsing behavior remains intact and tests cover the new admin access path and the removed comment surface.

## Blocked by

None - can start immediately.

## User stories addressed

Reference by number from the parent PRD:

- User story 2
- User story 3
- User story 4
- User story 5
- User story 11
- User story 29
- User story 30