Let each install pick its app icon

Settings > General gets an App icon (super admin): one of the seven
stones, or an uploaded image with the picked stone as a top-left corner
mark (inside a round launcher's crop, clear of the browser's badge),
previewed in both launcher crops before saving.

Uploads are decoded and cropped to a stored square (no SVG); the set is
drawn into DATA_DIR/install-icon/<version>/ and served publicly and
immutable. The manifest, head icon links and push notifications point at
it; the ember stone keeps the stock icons. The generator shares the icon
renderer.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/pages/admin/settings/general/index.tsx

@@ -1,4 +1,5 @@
 import AppearanceSection from "./(sections)/appearance-section";
+import InstallIconSection from "./(sections)/install-icon-section";
 import InstallNameSection from "./(sections)/install-name-section";
 import NotificationsSection from "./(sections)/notifications-section";
 import PromptSection from "./(sections)/prompt-section";
@@ -15,8 +16,9 @@ export default function AdminSettingsGeneralPage() {
             title="General"
             description="How the app looks and behaves."
         >
-            <AppearanceSection />
             <InstallNameSection />
+            <InstallIconSection />
+            <AppearanceSection />
             <NotificationsSection />
             <PromptSection />
             <RunLimitsSection />