fix(web): code review round 3 -- UI bugs and remaining design fidelity

- FileAttachment never surfaced a failed authenticated download -- the
  card looked identically clickable whether it worked or not, and
  clicking while broken silently no-op'd. Added an error state/retry
  (useAuthedBlobUrl gained a retry() escape hatch for this).
  ImageAttachment/AudioAttachment already handled this; only the file
  card didn't.
- --shadow-btn was one token serving two different specs: round 2's fix
  (0 6px 16px, from the 50px auth CTAs) actually regressed the 36px
  messaging send button (ConversationView/VoiceRecorder), which needs
  0 4px 12px per 02-messages.dc.html. Split into --shadow-btn /
  --shadow-btn-sm.
- loadOlder's scroll-restore guard compared topicId by value, which
  false-positives on an A->B->A round trip within one request's
  lifetime (same string, but the DOM was torn down and rebuilt by the
  intervening open/close). Switched to a generation counter, same
  pattern as topics.ts's leave-race fix.
- errorToast wasn't included in ConversationView/DetailColumn's
  topicId-reset effects -- a failed action's toast could keep showing
  over a conversation/contact switched to afterward. Also switched
  those effects (and MessagesLayout's) from useEffect to
  useLayoutEffect -- since none of these components remount on
  topicId change, a post-paint effect could let one frame render with
  the previous topicId's stale UI still showing.
- VoiceRecorder never listened for MediaRecorder's own onerror -- a
  mid-recording failure left the "录音中" timer ticking forever with no
  indication the recording had already died.
- VerificationCodeButton's phone-change countdown reset (round 2) only
  cleared the button's own state; RegisterPage/ResetPasswordPage's
  challengeId was still tied to whatever phone the code was actually
  issued for, with nothing cross-checking it against a since-edited
  phone number.
- Agreement's checkbox used bare accent-color on a native input, which
  only tints the checked fill and leaves size/radius/border to the
  browser/OS; replaced with the spec's exact 16x16 border-radius:4px
  box + check glyph.
- Added a catch-all route (App.tsx), TenantFeedbackPage image-picker
  validation feedback + corrected remove-button style, and a handful of
  smaller token/spacing corrections against screens/*.dc.html (NavRail
  font-weight, LoginPage/TenantEntryPage logo size+shadow+color,
  ChatListColumn row padding/icon size, --shadow-modal alpha).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/features/messages/DetailColumn.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState } from 'react';
+import { useLayoutEffect, useState } from 'react';
 
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
 import { useNavigate } from 'react-router-dom';
@@ -56,10 +56,14 @@ export function DetailColumn({ topicId, peerName, onClose, onOpenHistory }: Deta
 
   // DetailColumn is reused across every contact when docked (no `key={topicId}`, same instance),
   // so without this an in-progress remark edit for the PREVIOUS contact stays open and could be
-  // saved against the NEW one.
-  useEffect(() => {
+  // saved against the NEW one, and a leftover error toast would keep showing over the new contact
+  // misattributing the failure. useLayoutEffect (not useEffect) so this resolves before paint --
+  // this component never remounts on topicId change, so a post-paint effect can let one frame
+  // render with the previous contact's stale edit box still open.
+  useLayoutEffect(() => {
     setRemarkEditing(false);
     setRemarkDraft('');
+    setErrorToast('');
   }, [topicId]);
 
   const friendsQuery = useQuery({ queryKey: ['friends'], queryFn: () => fetchAllPages((cursor) => getFriends('', cursor)) });
@@ -98,7 +102,7 @@ export function DetailColumn({ topicId, peerName, onClose, onOpenHistory }: Deta
   });
 
   const blocksQuery = useQuery({ queryKey: ['blocks'], queryFn: () => fetchAllPages((cursor) => getBlocks(cursor)) });
-  const isBlocked = !!blocksQuery.data?.some((b) => b.user_id === topicId);
+  const isBlocked = !!blocksQuery.data?.some((b) => b.user.user_id === topicId);
 
   const deleteFriendMutation = useMutation({
     mutationFn: () => deleteFriend(topicId),