Add installable-app manifest, icons, and iOS splash screens

docs/dev.md

@@ -39,3 +39,4 @@ switches the directory app to the Google Sheets source. At startup the directory
 - `web/directory` — directory app page templates and static assets
 - `tools/screenshot` — dev-site page capture, see [screenshots.md](screenshots.md)
 - `tools/columns` — print the column names of each directory table in the configured source
+- `tools/splash` — extract the original app's iOS splash screens into `web/static/brand/splash`

docs/plan.md

@@ -4,7 +4,6 @@ What remains to build. Current behavior is documented in `docs/dev.md`, `docs/da
 
 ## Directory app
 
-- Installable-app plumbing: manifest, icons, and meta tags per `docs/pwa.md`.
 - Self-service flows: photo and pronunciation upload, address update, opt-out.
 
 ## Hosting and deployment

docs/pwa.md

@@ -11,10 +11,10 @@ The directory is used from phone home screens, so Heliosian ships as an installa
 
 ## What Heliosian serves
 
-- `manifest.webmanifest` from the binary: name, short name, `display: standalone`, `start_url: /`, theme and background color `#014E54`, icons 192 and 512 as `any` plus maskable variants (maskable art keeps the lockup inside the safe zone on a full-bleed teal square).
-- Base template meta: `theme-color`, `viewport` including `viewport-fit=cover`, the two `apple-mobile-web-app-*` tags, and a 180px `apple-touch-icon`.
+- `manifest.webmanifest` at `/static/manifest.webmanifest` — under `/static/` because browsers fetch manifests without credentials and that path bypasses the sign-in wall. `scope` and `start_url` are `/`; name, `display: standalone`, theme and background color `#014E54`; icons 192 and 512 as `any` plus a 512 maskable (the maskable art keeps the lockup inside the safe zone on a full-bleed teal square). The server registers the `application/manifest+json` MIME type.
+- Both page templates (app and login) carry the manifest link, `theme-color` (light surface on the app page, teal on login), `viewport` including `viewport-fit=cover` and `user-scalable=no`, the two `apple-mobile-web-app-*` tags, 16/32 favicons, and the `apple-touch-icon`.
 - HTTPS comes with Cloud Run; installability requires it.
-- Splash screens for iOS are pre-rendered at the device-size matrix like the original; until that exists, launches show a plain background, which is acceptable.
+- Splash screens for iOS: both templates carry the original's full `apple-touch-startup-image` battery — 32 pre-rendered PNGs (the logo lockup on teal) covering every iPhone/iPad class in both orientations, served from `/static/brand/splash/`. `tools/splash` regenerates them by extracting the link matrix and images from the captured original page source.
 - A service worker is optional for install on current Chromium and adds offline shell caching; if added, it stays minimal — cache the static shell, never cache directory data (community data must not persist on shared devices beyond the session's needs).
 - `start_url` must resolve for a signed-out user by landing on the sign-in flow, then into the app.