fix(web): drop install-time PWA app-shell precache

Keep the web manifest and runtime caches so the app stays installable. Stop precaching JS/CSS/HTML at install time so adding locales or editor code cannot block desktop releases.

.github/workflows/desktop-build.yml

@@ -262,7 +262,7 @@ jobs:
           EDGE_EVER_DESKTOP_BUILD: "1"
         run: bun run build:web
 
-      - name: Verify Web precache budget
+      - name: Verify Web performance budget
         if: matrix.shared_validation
         run: bun run verify:web-performance