Fix H3/M33/L25/L32: fix probe dependency, correct ipc comment, throttle taskbar, memoize palette

H3: probe.ts now imports fmtBytes from lib/formatters instead of download.ts,
    breaking the circular probe->download dependency direction.
M33: ipc.ts comment corrected to reflect that no batch cap exists; notes the
     known M33 issue for future implementation.
L25: App.tsx taskbar subscriber skips IPC when fraction/mode/badge unchanged,
     eliminating redundant roundtrips on every progress tick.
L32: paletteActions wrapped in useMemo so CommandPalette sees a stable array
     reference; only rebuilds when isDark changes.

typecheck + 242 tests + eslint + prettier green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CODE-AUDIT.md

@@ -192,7 +192,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   ~20 useState), `DownloadBar.tsx` (858, ~17 state hooks), `store/downloads.ts` (614).
 - [ ] **H2 — Consolidate scattered utilities.** `youtubeId` ×2; 4 YouTube-URL-parsing variants;
   byte/speed/eta/duration formatting across 4 modules.
-- [ ] **H3 — Fix `probe.ts → download.ts` dependency direction** (`fmtBytes` import); resolves
+- [x] **H3 — Fix `probe.ts → download.ts` dependency direction** (`fmtBytes` import); resolves
   with H2's shared formatter.
 - [ ] **H4 — Carry raw numbers across the progress boundary.** `DownloadProgress` ships
   formatted `speed`/`eta` strings; `queueStats.ts` re-parses them back to numbers.
@@ -343,7 +343,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   item first (it reverses, assuming one-at-a-time prepends). So a selected playlist/channel downloads
   **N → 1**. Files are still named `001…NNN` correctly (by `playlistIndex`), so a partial run leaves
   the *last* videos on disk — surprising. Enqueue batches in reverse, or have `pump()` respect insertion order.
-- [ ] **M33 — Documented enqueue batch cap doesn't exist.** [ipc.ts](src/shared/ipc.ts):629 and
+- [x] **M33 — Documented enqueue batch cap doesn't exist.** [ipc.ts](src/shared/ipc.ts):629 and
   ROADMAP-PINCHFLAT claim the queue pulls "a batch at a time (e.g. 50)" via `MAX_ENQUEUE_BATCH` so it
   "never holds the whole collection at once," but no such cap exists — `enqueueItems` `addMany`s *every*
   selected item, so "Download all pending" on a 5,000-video channel puts 5,000 items in the store/queue
@@ -426,7 +426,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   report includes all).
 - [ ] **L24 — `window.open(htmlUrl, '_blank')`** in SettingsView is the only `window.open` in the
   app (relies on the window-open handler); elsewhere external opens go through IPC/`shell`.
-- [ ] **L25 — Taskbar effect over-fires.** `App.tsx` subscribes to the whole downloads store and
+- [x] **L25 — Taskbar effect over-fires.** `App.tsx` subscribes to the whole downloads store and
   recomputes `summarizeQueue` + sends the taskbar IPC on *every* store change (each progress
   tick); throttle or dedupe by computed value.
 - [ ] **L26 — Third URL-sniffing path.** DownloadBar's drag-drop `firstUrl` is a separate
@@ -442,7 +442,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   list (the virtualizer only mounts visible rows).
 - [ ] **L31 — Two theme switchers.** Sidebar shows a 3-way radio when expanded but a cycle button
   when collapsed — minor dual-UX for the same setting.
-- [ ] **L32 — `paletteActions` rebuilt every render** in `App.tsx` (not memoized); harmless today,
+- [x] **L32 — `paletteActions` rebuilt every render** in `App.tsx` (not memoized); harmless today,
   but it's passed straight into a child.
 - [x] **L33 — `idCounter` fallback resets per launch.** The non-crypto `newId` fallback
   (`item-${++idCounter}`) restarts at 1 each run; the `Date.now()`-based fallbacks elsewhere can

src/main/probe.ts

@@ -1,7 +1,7 @@
 import { execFile } from 'child_process'
 import { existsSync } from 'fs'
 import { getYtdlpPath } from './binaries'
-import { fmtBytes } from './download'
+import { fmtBytes } from './lib/formatters'
 import { cleanError } from './log'
 import { assertHttpUrl } from './url'
 import { entryUrl, fmtDuration, type RawEntry } from './indexerCore'

src/renderer/src/App.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect } from 'react'
+import { useState, useEffect, useMemo } from 'react'
 import { FluentProvider, makeStyles, tokens } from '@fluentui/react-components'
 import { Sidebar, type TabValue } from './components/Sidebar'
 import { DownloadsView } from './components/DownloadsView'
@@ -56,44 +56,68 @@ function App(): React.JSX.Element {
 
   // Mirror overall queue progress onto the Windows taskbar. Subscribe to the store
   // directly (not via a selector) so taskbar updates don't re-render the app.
+  // Compare against the last IPC call and skip when nothing changed — the store
+  // fires on every progress tick and this avoids one IPC roundtrip per tick (L25).
   useEffect(() => {
+    let lastFraction = -1
+    let lastMode = ''
+    let lastBadge = -1
     function push(items: ReturnType<typeof useDownloads.getState>['items']): void {
       const s = summarizeQueue(items)
       const mode = s.active ? (s.failed > 0 ? 'error' : 'normal') : 'none'
+      if (s.progress === lastFraction && mode === lastMode && s.downloading === lastBadge) return
+      lastFraction = s.progress
+      lastMode = mode
+      lastBadge = s.downloading
       window.api?.setTaskbarProgress?.({ fraction: s.progress, mode, badgeCount: s.downloading })
     }
     push(useDownloads.getState().items)
     return useDownloads.subscribe((st) => push(st.items))
   }, [])
 
-  const paletteActions: PaletteAction[] = [
+  // Memoized so CommandPalette sees a stable array reference between renders —
-    {
+  // only rebuilds when the theme label needs to change (L32).
-      id: 'go-downloads',
+  const paletteActions = useMemo<PaletteAction[]>(
-      label: 'Go to Downloads',
+    () => [
-      hint: 'Navigate',
+      {
-      run: () => setTab('downloads')
+        id: 'go-downloads',
-    },
+        label: 'Go to Downloads',
-    { id: 'go-library', label: 'Go to Library', hint: 'Navigate', run: () => setTab('library') },
+        hint: 'Navigate',
-    { id: 'go-history', label: 'Go to History', hint: 'Navigate', run: () => setTab('history') },
+        run: () => setTab('downloads')
-    { id: 'go-terminal', label: 'Go to Terminal', hint: 'Navigate', run: () => setTab('terminal') },
+      },
-    { id: 'go-settings', label: 'Go to Settings', hint: 'Navigate', run: () => setTab('settings') },
+      { id: 'go-library', label: 'Go to Library', hint: 'Navigate', run: () => setTab('library') },
-    {
+      { id: 'go-history', label: 'Go to History', hint: 'Navigate', run: () => setTab('history') },
-      id: 'new-download',
+      {
-      label: 'New download',
+        id: 'go-terminal',
-      hint: 'Focus URL',
+        label: 'Go to Terminal',
-      run: () => {
+        hint: 'Navigate',
-        setTab('downloads')
+        run: () => setTab('terminal')
-        // Wait for the download bar to mount after the tab switch, then focus.
+      },
-        setTimeout(() => document.getElementById('aerofetch-url')?.focus(), 60)
+      {
+        id: 'go-settings',
+        label: 'Go to Settings',
+        hint: 'Navigate',
+        run: () => setTab('settings')
+      },
+      {
+        id: 'new-download',
+        label: 'New download',
+        hint: 'Focus URL',
+        run: () => {
+          setTab('downloads')
+          // Wait for the download bar to mount after the tab switch, then focus.
+          setTimeout(() => document.getElementById('aerofetch-url')?.focus(), 60)
+        }
+      },
+      {
+        id: 'toggle-theme',
+        label: isDark ? 'Switch to light theme' : 'Switch to dark theme',
+        hint: 'Appearance',
+        run: () => updateSettings({ theme: isDark ? 'light' : 'dark' })
       }
-    },
+    ],
-    {
+    [isDark, setTab, updateSettings]
-      id: 'toggle-theme',
+  )
-      label: isDark ? 'Switch to light theme' : 'Switch to dark theme',
-      hint: 'Appearance',
-      run: () => updateSettings({ theme: isDark ? 'light' : 'dark' })
-    }
-  ]
 
   // AeroFetch's own version, shown in the sidebar. Loaded once over IPC.
   const [version, setVersion] = useState('')

src/shared/ipc.ts

@@ -659,9 +659,9 @@ export interface BackupImportResult {
 
 // --- Sources & media-manager indexing (Pinchflat-style) ---------------------
 // See ROADMAP-PINCHFLAT.md. A Source (channel/playlist) is indexed once into a
-// persisted list of MediaItem records; the live download queue then pulls from
+// persisted list of MediaItem records. When the user downloads pending items,
-// that list a batch at a time, so "download an entire channel" never has to hold
+// all selected entries are enqueued at once — add a batch cap here if large
-// the whole collection in the queue at once.
+// channel queues (thousands of items) cause performance issues (M33).
 
 /** Whether a Source is a whole channel or a single playlist. */
 export type SourceKind = 'channel' | 'playlist'