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/utils/parse-install-icon.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, test } from "bun:test";
+import { PwaDefaultInstallIcon } from "@/src/data/pwa-data";
+import parseInstallIcon from "./parse-install-icon";
+
+describe("parseInstallIcon", () => {
+    test("falls back to the stock icon when nothing or junk is saved", () => {
+        expect(parseInstallIcon({})).toEqual(PwaDefaultInstallIcon);
+        expect(parseInstallIcon({ saved: "not json" })).toEqual(PwaDefaultInstallIcon);
+        expect(parseInstallIcon({ saved: "[1]" })).toEqual(PwaDefaultInstallIcon);
+    });
+
+    test("reads a saved icon", () => {
+        expect(
+            parseInstallIcon({
+                saved: JSON.stringify({ mode: "image", stone: "cobalt", mark: false, version: "0123456789ab" }),
+            }),
+        ).toEqual({ mode: "image", stone: "cobalt", mark: false, version: "0123456789ab" });
+    });
+
+    test("drops unknown values field by field", () => {
+        expect(
+            parseInstallIcon({
+                saved: JSON.stringify({ mode: "video", stone: "plaid", mark: "yes", version: "../etc" }),
+            }),
+        ).toEqual(PwaDefaultInstallIcon);
+    });
+});