feat: optimize profile image sizes, silent PWA updates, storage cleanup fixes

- Resize avatars/icons to 256px and banners to 1280px (client crop + server safety net)
- Add server-side resizeProfileImage() for federation/API uploads without crop modal
- Fix unconstrained crop on RegisterPage and CreateSpace (was missing maxOutputDimension)
- PWA: switch to autoUpdate with skipWaiting/clientsClaim for seamless deploys
- Storage janitor: exclude profile images from unlinked cleanup, delete stale thumbnails
- Add deleteAttachmentByFilename() to clean orphaned attachment records for profile images
- Migration: one-time cleanup of stale profile image attachment records
- GeneralPanel: wrap in <form> to prevent implicit submission

packages/web/src/components/modals/settingsPanels/AccountPanel.tsx

@@ -741,7 +741,7 @@ export function AccountPanel() {
         title="Crop Avatar"
         cropShape="round"
         aspectRatio={1}
-        maxOutputDimension={512}
+        maxOutputDimension={256}
       />
       <ImageCropModal
         isOpen={bannerCropSrc !== null}
@@ -751,7 +751,7 @@ export function AccountPanel() {
         title="Crop Banner"
         cropShape="rect"
         aspectRatio={3}
-        maxOutputDimension={1920}
+        maxOutputDimension={1280}
       />
 
       <DeleteAccountModal