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/lintProbe.testkit.ts

@@ -9,7 +9,31 @@ import { beforeAll } from "vitest";
 // hook below pays that cost once per test file, under its own budget; importing this registers it.
 const FRONTEND = fileURLToPath(new URL("../../", import.meta.url));
 
-export const eslint = new ESLint({ cwd: FRONTEND });
+// The probes lint TEXT under file names that do not exist (`__probe.tsx`, `x.ts`, a feature-folder
+// `Button.tsx`). Since E32 the src config runs type-aware rules, whose project service refuses a
+// file no tsconfig includes, so those names are let into TypeScript's default project here — the
+// probe still runs the real config, typed rules included, rather than a copy with them switched off.
+const PROBE_FILES = [
+  "src/*/__*probe.ts",
+  "src/*/__*probe.tsx",
+  "src/components/ui/__*probe.tsx",
+  "src/lib/api/__*probe.ts",
+  "src/components/Button.tsx",
+  "src/lib/x.ts",
+];
+
+export const eslint = new ESLint({
+  cwd: FRONTEND,
+  overrideConfig: {
+    files: ["src/**/*.{ts,tsx}"],
+    languageOptions: {
+      parserOptions: {
+        projectService: { allowDefaultProject: PROBE_FILES, defaultProject: "tsconfig.json" },
+        tsconfigRootDir: FRONTEND,
+      },
+    },
+  },
+});
 
 beforeAll(async () => {
   await eslint.lintText("", { filePath: "src/components/__probe.tsx" });