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/lib/modules.ts

@@ -13,9 +13,9 @@ import {
   SlidersHorizontal,
   Tv,
   Users,
-  Youtube,
   type LucideIcon,
 } from "lucide-react";
+import { YouTubeIcon } from "./brandIcons";
 import type { Me } from "./api";
 import type { Page } from "./urlState";
 
@@ -62,7 +62,7 @@ const MODULES: readonly ModuleDef[] = [
     titleKey: "home.title",
     icon: Home,
   },
-  { id: "feed", labelKey: "header.account.feed", railKey: "nav.rail.feed", icon: Youtube },
+  { id: "feed", labelKey: "header.account.feed", railKey: "nav.rail.feed", icon: YouTubeIcon },
   {
     id: "channels",
     labelKey: "header.account.channels",