build(frontend): close the lint gaps the E32 audit measured

eslint now also enforces:
- the React Compiler diagnostics that `recommended` leaves out (todo,
  memo-dependencies and ten zero-hit tripwires);
- a description on every suppression, and no blanket disables;
- no focused or skipped tests (vitest and playwright);
- the typed pair no-floating-promises and no-deprecated.

Lint also covers e2e/ and the TypeScript build configs, which `eslint .`
had been skipping in silence.

Every hit is fixed or suppressed inline with a named reason:
- The 31 try statements the compiler cannot lower yet carry a suppression
  until S3 rewrites them. Five other compiler skips were plain fixes:
  a module counter bumped inside a hook, a ref read in a default
  parameter, and a local named like the <section> it renders.
- The real defects behind floating promises are fixed. ChatDock threw at
  nobody when the device key store could not be opened. VideoEditor's
  play() rejection went unhandled. loadYouTubeApi never rejected, so a
  blocked IFrame API left the player on an empty stage forever; it now
  fails on a script error or after 15 s, shows its own error with the
  way out, and lets the next open try again.
- MutableRefObject, FormEvent and lucide's deprecated brand icon are
  replaced. The YouTube glyph now lives in lib/brandIcons.
- The lint-probe harness lets its virtual file names into TypeScript's
  default project, so the contract tests still run the real config.

frontend/src/components/Playlists.tsx

@@ -18,7 +18,8 @@ import {
   verticalListSortingStrategy,
 } from "@dnd-kit/sortable";
 import { CSS } from "@dnd-kit/utilities";
-import { Check, FolderInput, History, ListPlus, Play, X, Youtube } from "lucide-react";
+import { Check, FolderInput, History, ListPlus, Play, X } from "lucide-react";
+import { YouTubeIcon } from "../lib/brandIcons";
 import { api, type Playlist, type PlaylistDetail, type Video } from "../lib/api";
 import { notify } from "../lib/notifications";
 import { notifyActionError } from "../lib/actionErrors";
@@ -460,10 +461,10 @@ export default function Playlists() {
    *  the X column became the Delete key + this toast; no confirm, because nothing is lost).
    *  @returns whether the item was actually removed — the player needs to know, because it must
    *  step to the next item (or close) only when the removal really happened. */
-  async function removeItem(
-    video: Video,
-    listId: number | null = selectedRef.current,
-  ): Promise<boolean> {
+  async function removeItem(video: Video, listIdArg?: number | null): Promise<boolean> {
+    // Defaulted here, not as `listId = selectedRef.current` in the signature: the React Compiler
+    // cannot reorder a ref read in a default parameter and skipped the component for it.
+    const listId = listIdArg === undefined ? selectedRef.current : listIdArg;
     if (listId == null) return false;
     // Only the list ON SCREEN has rows to take the item out of optimistically — the open player can
     // be removing from the list it was launched from while another one is selected.
@@ -685,7 +686,7 @@ export default function Playlists() {
                       label: plName(pl),
                       icon:
                         pl.source === "youtube" || pl.yt_playlist_id ? (
-                          <Youtube className="w-4 h-4" />
+                          <YouTubeIcon className="w-4 h-4" />
                         ) : (
                           <ListPlus className="w-4 h-4" />
                         ),
@@ -866,7 +867,7 @@ export default function Playlists() {
                       onKeyDown={(e) => {
                         if (e.key === "Enter") {
                           renameFocus.arm(e);
-                          saveRename();
+                          void saveRename(); // plActions.rename reports its own failure
                         }
                         if (e.key === "Escape") {
                           renameFocus.arm(e);