diff --git a/CODE-AUDIT.md b/CODE-AUDIT.md
index 99273cc..3c28ddf 100644
--- a/CODE-AUDIT.md
+++ b/CODE-AUDIT.md
@@ -438,7 +438,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   ref; changing the default in Settings while on the Downloads tab isn't reflected until reload.
 - [ ] **L29 — UI constant in the store.** `QUALITY_OPTIONS` lives in `store/downloads.ts` yet is a
   presentational constant imported by views — couples UI to the store module.
-- [ ] **L30 — Redundant `loading="lazy"`** on `MediaThumb` images already inside a virtualized
+- [x] **L30 — Redundant `loading="lazy"`** on `MediaThumb` images already inside a virtualized
   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.
@@ -465,7 +465,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
   URL (surfaced by the NSIS installer).
 - [x] **L42 — `package.json` has no `license` field** (ships LGPL ffmpeg + GPL aria2c).
 - [x] **L43 — `package.json` has no `repository` field** (real repo is the Gitea instance).
-- [ ] **L44 — Vestigial lint excludes.** `electron-builder.yml` excludes `.eslintrc`/`.prettierrc`
+- [x] **L44 — Vestigial lint excludes.** `electron-builder.yml` excludes `.eslintrc`/`.prettierrc`
   but there's no ESLint/Prettier config, script, or dependency — no enforced style tooling.
 - [x] **L45 — Three self-descriptions** drift: pkg `description` "A yt-dlp frontend for Windows" vs
   builder `copyright` "yt-dlp frontend" vs Sidebar caption "yt-dlp frontend".
@@ -493,7 +493,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
 - [x] **L58 — `chooseFolder` passes the macOS-only `createDirectory` property** — dead option on Windows.
 - [ ] **L59 — `THEME_BACKGROUND` (index.ts) duplicates `pageBackground` (theme.ts)** — two
   hand-synced color constants (a "keep in sync" comment guards them).
-- [ ] **L60 — `'external-url'` channel name lacks the `category:` prefix** every other IPC channel uses.
+- [x] **L60 — `'external-url'` channel name lacks the `category:` prefix** every other IPC channel uses.
 - [ ] **L61 — `taskbarProgress` is the lone `ipcMain.on`** (fire-and-forget) amid all-`invoke` channels.
 - [ ] **L62 — "Best available" synthetic format hardcodes `ext:'mp4'`/`hasAudio:true`** (probe.ts) —
   mislabels when the chosen container is mkv/webm.
@@ -555,7 +555,7 @@ token system + shared primitives (UI/SIMP — high value, larger effort) · i18n
 
 *Round 5 (2026-06-29) — code-level micro-inconsistencies & polish:*
 
-- [ ] **L90 — Two idioms for "value in const array."** [settings.ts](src/main/settings.ts) `sanitizeOptions`
+- [x] **L90 — Two idioms for "value in const array."** [settings.ts](src/main/settings.ts) `sanitizeOptions`
   uses `ARR.includes(x as never)` (L116–120) while `setSettings` uses `(ARR as readonly string[]).includes(x as string)` (L275/323). Pick one.
 - [x] **L91 — Unsafe tuple cast / fragile encoding.** `value.split('|') as [MediaKind, string]`
   ([SettingsView.tsx](src/renderer/src/components/SettingsView.tsx):411) trusts a `'|'`-joined
diff --git a/electron-builder.yml b/electron-builder.yml
index 653a267..763f6a5 100644
--- a/electron-builder.yml
+++ b/electron-builder.yml
@@ -23,7 +23,7 @@ files:
   - '!**/.vscode/*'
   - '!src/*'
   - '!electron.vite.config.{js,ts,mjs,cjs}'
-  - '!{.eslintignore,.eslintrc.cjs,.eslintrc.js,.prettierignore,.prettierrc.yaml,dev-app-update.yml,CHANGELOG.md,README.md}'
+  - '!{eslint.config.js,.prettierrc,dev-app-update.yml,CHANGELOG.md,README.md}'
   - '!{.env,.env.*,.npmrc,pnpm-lock.yaml,package-lock.json}'
   - '!{tsconfig.json,tsconfig.node.json,tsconfig.web.json}'
   - '!*.tsbuildinfo'
diff --git a/src/main/settings.ts b/src/main/settings.ts
index 4b3199d..7876529 100644
--- a/src/main/settings.ts
+++ b/src/main/settings.ts
@@ -16,7 +16,10 @@ import {
   isYtdlpUpdateChannel,
   type Settings,
   type DownloadOptions,
-  type SponsorBlockCategory
+  type SponsorBlockCategory,
+  type AudioFormat,
+  type VideoContainer,
+  type VideoCodecPref
 } from '@shared/ipc'
 
 const DEFAULTS: Settings = {
@@ -121,12 +124,16 @@ function sanitizeOptions(input: unknown): DownloadOptions {
       ) as SponsorBlockCategory[])
     : d.sponsorBlockCategories
   return {
-    audioFormat: AUDIO_FORMATS.includes(o.audioFormat as never) ? o.audioFormat! : d.audioFormat,
-    videoContainer: VIDEO_CONTAINERS.includes(o.videoContainer as never)
-      ? o.videoContainer!
+    audioFormat: (AUDIO_FORMATS as readonly string[]).includes(o.audioFormat as string)
+      ? (o.audioFormat as AudioFormat)
+      : d.audioFormat,
+    videoContainer: (VIDEO_CONTAINERS as readonly string[]).includes(o.videoContainer as string)
+      ? (o.videoContainer as VideoContainer)
       : d.videoContainer,
-    preferredVideoCodec: VIDEO_CODECS.includes(o.preferredVideoCodec as never)
-      ? o.preferredVideoCodec!
+    preferredVideoCodec: (VIDEO_CODECS as readonly string[]).includes(
+      o.preferredVideoCodec as string
+    )
+      ? (o.preferredVideoCodec as VideoCodecPref)
       : d.preferredVideoCodec,
     formatSort: typeof o.formatSort === 'string' ? o.formatSort.trim() : d.formatSort,
     embedSubtitles: bool(o.embedSubtitles, d.embedSubtitles),
diff --git a/src/renderer/src/components/MediaThumb.tsx b/src/renderer/src/components/MediaThumb.tsx
index bc1e0fd..727d66c 100644
--- a/src/renderer/src/components/MediaThumb.tsx
+++ b/src/renderer/src/components/MediaThumb.tsx
@@ -53,13 +53,7 @@ export function MediaThumb({
       style={{ backgroundColor: colors.bg, color: colors.fg }}
     >
       {showImg ? (
-        <img
-          className={styles.img}
-          src={src}
-          alt=""
-          loading="lazy"
-          onError={() => setFailedSrc(src ?? null)}
-        />
+        <img className={styles.img} src={src} alt="" onError={() => setFailedSrc(src ?? null)} />
       ) : kind === 'audio' ? (
         <MusicNote2Regular fontSize={iconSize} />
       ) : (
diff --git a/src/shared/ipc.ts b/src/shared/ipc.ts
index 3085770..ffd98cc 100644
--- a/src/shared/ipc.ts
+++ b/src/shared/ipc.ts
@@ -56,7 +56,7 @@ export const IpcChannels = {
   preloadBridgeFailure: 'preload:bridge-failure',
   /** main → renderer push channel: a URL handed to AeroFetch from outside the app
    *  (the aerofetch:// protocol, or a .url file via Explorer's "Send to" menu) */
-  externalUrl: 'external-url',
+  externalUrl: 'app:external-url',
   // --- Sources & media-manager indexing (Pinchflat-style, see ROADMAP-PINCHFLAT.md) ---
   sourcesList: 'sources:list',
   sourceIndex: 'sources:index',