docs(comments): correct comments the cuts left stale

The registration language is read today (preferences.language, the mail language); the Modal and
the players order against popovers through layerStack, not the FloatingTree; the upload's auth
dependency is current_user; the module of access tests covers onboarding and access, not only the
canonical email. The dev proxy's WebSocket upgrade served the removed messages socket and goes; the
test compose header says a pure-logic run needs SIFTLODE_TEST_REQUIRE_DB=0; the speed measure no
longer reports an unreachable database as "no share link".

frontend/vite.config.ts

@@ -12,10 +12,7 @@ const target = "http://127.0.0.1:8080";
 // server returns to :5173 instead of the fixed :8080 callback. (Both are registered in the console.)
 const proxyOpts = { target, changeOrigin: false };
 const proxy = {
-  // ws: the in-app messages socket (/api/messages/ws) is a WebSocket. Without it Vite hands that upgrade
-  // to nobody, so the socket never connects on :5173 — and the first reset on it (a closed tab, a dropped
-  // connection) throws an unhandled ECONNRESET that takes the whole dev server down.
-  "/api": { ...proxyOpts, ws: true },
+  "/api": proxyOpts,
   "/auth": proxyOpts,
   "/healthz": proxyOpts,
 };