Steam library: safe removal and title matching, artwork within Steam's limit

- Remove: collections and artwork clearing are best effort in Steam's JS, and
  the host carries on to delete the files when Steam isn't running (Android
  apps and devkit titles).
- Devkit titles: the shortcut is found by devkit id, the saved id, or an
  executable/start folder inside the title's folder; never by display name.
  Steam's overviews don't carry devkit_gameid (checked on the Frame
  2026-09-28), so 'list' now reads exe/start dir from app details.
- Photo-based grid/wide/hero slots render as JPEG (a noise-heavy 3840x1240
  hero was over 12 MiB as PNG on the Frame); the logo stays transparent PNG.
  Rendering gets 75 s and retries once with generated art. Each slot is
  cleared before it is set, since Steam keeps .png and .jpg side by side.
- Devkit titles keep their own VR flag (vr=None skips SetShortcutIsVR) and
  their Sideloaded collection.
- A failed title install's cleanup can't replace the original error.
- refresh_art for devkit titles (frame_titles.refresh_art).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/fakeframe/rootfs/usr/local/lib/fakeframe/canvas_stub.js

@@ -23,7 +23,8 @@ function surface() {
       drawImage(){canvas.draws++;},getImageData:()=>({data:new Uint8ClampedArray(canvas.width*canvas.height*4)}),
       createLinearGradient:()=>({addColorStop(){}}),createRadialGradient:()=>({addColorStop(){}})};
     for(const method of ['save','restore','beginPath','rect','roundRect','clip','fillRect','putImageData','arc','fill','stroke'])ctx[method]=()=>{};
-    canvas.getContext=()=>ctx;canvas.toDataURL=()=> 'data:image/png;base64,'+png(canvas.width,canvas.height);
+    canvas.getContext=()=>ctx;canvas.toDataURL=type=>type==='image/jpeg'?'data:image/jpeg;base64,'+Buffer.from('ffd8ffe000104a464946','hex').toString('base64'):
+      'data:image/png;base64,'+png(canvas.width,canvas.height);
     canvases.push(canvas);return canvas;
   }};
   class Image {constructor(){this.width=2;this.height=2;} async decode(){if(this.src.includes('YmFk'))throw Error('bad image');}}

tests/fakeframe/rootfs/usr/local/lib/fakeframe/cef_shim.js

@@ -71,6 +71,13 @@ function build(steam) {
       NewUnsavedCollection(name, filter, apps) { return collection({name, apps: apps.map(a => a.appid)}); },
       async SaveCollection(c) { if (!steam.collections.includes(c.value)) steam.collections.push(c.value); },
     },
+    // Shortcut exe/start folder live in app details, not overviews (Frame, 2026-09-28).
+    appDetailsStore: {
+      GetAppDetails(id) {
+        const s = findShortcut(id);
+        return s ? { strShortcutExe: s.exe, strShortcutStartDir: s.start_dir, bShortcutIsVR: !!s.vr } : null;
+      },
+    },
     appStore: {
       get allApps() { return allApps(); },
       GetAppOverviewByAppID(id) { return allApps().find(a => a.appid === Number(id)) || null; },