## ADDED Requirements

### Requirement: Critical assets do not remain stale after deploy
The service worker and server caching strategy MUST ensure critical shell assets (including the global stylesheet and service worker script) do not remain stale across deploys.

The implementation MUST include at least one cache-busting mechanism for critical assets, such as:

- content-hashed asset filenames, or
- an asset version query suffix that changes per deploy

#### Scenario: New deploy updates critical CSS
- **WHEN** a new deploy is released and a returning user loads the site
- **THEN** the user receives the updated global stylesheet without requiring a manual hard refresh

#### Scenario: Service worker updates predictably
- **WHEN** a new deploy is released
- **THEN** the browser can retrieve the updated service worker script and activate it without being pinned by long-lived caches
