docs(desktop): explain the remaining node builtin suppressions

Every `nodeBuiltinImport:off` in the import module now says which builtin it
covers and why Effect has no equivalent, matching the neighbouring preload and
Playwright modules.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: juliusmarminge

apps/desktop/src/preview/BrowserImport/ChromiumCookies.test.ts

@@ -1,4 +1,5 @@
-// @effect-diagnostics nodeBuiltinImport:off
+// @effect-diagnostics nodeBuiltinImport:off - Encrypts fixtures with the same
+// OSCrypt primitives the module under test decrypts.
 import { describe, expect, it } from "@effect/vitest";
 import * as NodeCrypto from "node:crypto";