Installable offline edition
- Adds a standards-based web app manifest and 192/512 px app icons.
- Adds a narrowly scoped service worker so the generator works offline after its first successful load.
- Adds an in-app install prompt when the browser supports it.
- Links the new free next-action checker.
- Adds tests for the manifest, icon assets, origin boundary, GET-only worker handling, and offline app shell.
The generator remains dependency-free and runs locally. It does not send messages, store form contents, or guarantee quote outcomes.