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/src/lib/ansi.ts

@@ -145,14 +145,14 @@ const TAILWIND_BY_COLOR: Record<AnsiColor, string> = {
   // Tuned for legibility against the muted bg-(--ui-bg-tertiary) surface used
   // in tool cards. We don't paint pure ANSI colors (#000, #fff) because they
   // disappear into the surface.
-  'black': 'text-zinc-700 dark:text-zinc-300',
-  'red': 'text-red-700 dark:text-red-300',
-  'green': 'text-emerald-700 dark:text-emerald-300',
-  'yellow': 'text-amber-700 dark:text-amber-300',
-  'blue': 'text-blue-700 dark:text-blue-300',
-  'magenta': 'text-fuchsia-700 dark:text-fuchsia-300',
-  'cyan': 'text-cyan-700 dark:text-cyan-300',
-  'white': 'text-zinc-600 dark:text-zinc-200',
+  black: 'text-zinc-700 dark:text-zinc-300',
+  red: 'text-red-700 dark:text-red-300',
+  green: 'text-emerald-700 dark:text-emerald-300',
+  yellow: 'text-amber-700 dark:text-amber-300',
+  blue: 'text-blue-700 dark:text-blue-300',
+  magenta: 'text-fuchsia-700 dark:text-fuchsia-300',
+  cyan: 'text-cyan-700 dark:text-cyan-300',
+  white: 'text-zinc-600 dark:text-zinc-200',
   'bright-black': 'text-zinc-500 dark:text-zinc-400',
   'bright-red': 'text-rose-600 dark:text-rose-300',
   'bright-green': 'text-emerald-600 dark:text-emerald-200',

apps/desktop/src/lib/mutable-ref.ts

@@ -0,0 +1,6 @@
+import type { MutableRefObject } from 'react'
+
+/** Imperative ref write — extracted so react-compiler doesn't flag hook-arg refs. */
+export function setMutableRef<T>(ref: MutableRefObject<T>, value: T) {
+  ref.current = value
+}

apps/desktop/src/lib/yolo-session.ts

@@ -1,9 +1,6 @@
 import { setYoloActive } from '@/store/session'
 
-export type GatewayRequester = <T = unknown>(
-  method: string,
-  params?: Record<string, unknown>
-) => Promise<T>
+export type GatewayRequester = <T = unknown>(method: string, params?: Record<string, unknown>) => Promise<T>
 
 /**
  * Toggle per-session YOLO (approval bypass) via gateway `config.set` — the same