chore(desktop): zero eslint/typecheck debt + prettier pass (#39100)

- eslint --fix across src/ and electron/ (unused imports, import/prop sort, padding)
- flatten empty catch blocks in electron CJS; drop unused applyUpdatesPosixInApp arg
- add setMutableRef helper for imperative ref writes (react-compiler clean)
- move sidebar cookie persistence into an effect; extract scrollElementToBottom helper

apps/desktop/electron/bootstrap-platform.cjs

@@ -52,7 +52,9 @@ function detectRemoteDisplay(options = {}) {
   const env = options.env ?? process.env
   const platform = options.platform ?? process.platform
 
-  const override = String(env.HERMES_DESKTOP_DISABLE_GPU || '').trim().toLowerCase()
+  const override = String(env.HERMES_DESKTOP_DISABLE_GPU || '')
+    .trim()
+    .toLowerCase()
   if (GPU_OVERRIDE_ON.has(override)) return 'override (HERMES_DESKTOP_DISABLE_GPU)'
   if (GPU_OVERRIDE_OFF.has(override)) return null