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/src/components/ui/AnchoredPopover.tsx

@@ -28,7 +28,8 @@ import type { useAnchoredPopover } from "./anchoredPopoverHooks";
 //   - autoUpdate → follows the trigger on scroll/resize (the old rAF loop), coalesced by the library
 // Positioning is portalled through FloatingPortal (escapes ancestor stacking contexts — same job the
 // house <Overlay> did for TagsCell). Every popover is a node in the app's <FloatingTree> so Escape /
-// outside-press dispatch is topmost-only across nested layers (the Modal and players included).
+// outside-press dispatch is topmost-only across nested popovers; against the Modal and the players,
+// which are not nodes, it is lib/layerStack that decides who is topmost.
 //
 // This layer adds the keyboard/ARIA model the roles promise, mirroring `ViewSwitcher` (the house's
 // textbook menu) but via Floating UI's idioms rather than a second hand-rolled roving engine: