## Single top-level banner (host chrome hidden) + dev architecture review

- **One banner.** The SG/App host chrome stacked its own bar above the site header, so App Mode showed two top-level banners. `app.json` now declares `hud.mode: "hidden"` (per AUTHORING.md — chrome row and nav row both hidden, iframe full-viewport; a small corner "× Exit app" pill remains). The site's own header is now the single banner. Revert path: `hud.mode: "minimal"` restores a slim vault-name/title row.
- **Dev review filed** at `team/roles/dev/reviews/v0.4.3__dev-review__architecture-process-and-recommendations.md` — fresh-eyes architecture/process review. Headline finding: design snapshots are rebuilt from live `src/shared/` so they aren't actually frozen; recommends freezing superseded versions as built artifacts before v0.5.0, committing the jsdom smoke suite, applying the open Ambassador copy fixes (FedRAMP = public-domain blocker), and adding content-data integrity gates before the next library batch.