fix(ux): repair broken in-app navigations under HashRouter

Three places used window.location.href to navigate to bare paths (/signers,
/messages/:npub, /settings). Under HashRouter those trigger a full page reload
to a non-hash path the router can't match — the user got a blank/404 flash
instead of the target screen.

- WhosSkating: DM button now uses useNavigate() instead of a reload.
- StashPage: "Learn About Signers" now uses <Link to="/signers"> (asChild).
- BackupReminder: "Back up now" now uses navigate() AND corrects the deep-link
  param from ?tab=security to ?section=security (SettingsPage reads ?section),
  which previously dropped the user on the settings root instead of Security.
  Also closes the reminder sheet on navigate.

Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>

src/components/BackupReminder.tsx

@@ -1,4 +1,5 @@
 import { useState, useEffect } from 'react';
+import { useNavigate } from 'react-router-dom';
 import { AlertTriangle, X, Download, CheckCircle } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
@@ -26,6 +27,7 @@ export function BackupReminder() {
   const [confirmed, setConfirmed] = useLocalStorage(BACKUP_CONFIRMED_KEY, false);
   const [showReminder, setShowReminder] = useState(false);
   const { t } = useTranslation();
+  const navigate = useNavigate();
 
   useEffect(() => {
     if (!user) {
@@ -57,7 +59,13 @@ export function BackupReminder() {
   };
 
   const handleBackupNow = () => {
-    window.location.href = '/settings?tab=security';
+    // Client-side nav (HashRouter). window.location.href forced a full reload to
+    // a non-hash path the router couldn't match — it dropped the user on a blank
+    // page instead of the security settings. navigate() keeps it in-app.
+    setShowReminder(false);
+    // SettingsPage deep-links via ?section=… (NOT ?tab=…) — using the wrong
+    // param silently dropped the user on the settings root instead of Security.
+    navigate('/settings?section=security');
   };
 
   if (!showReminder) return null;

src/components/WhosSkating.tsx

@@ -1,4 +1,4 @@
-import { Link } from 'react-router-dom';
+import { Link, useNavigate } from 'react-router-dom';
 import { nip19 } from 'nostr-tools';
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 import { Avatar, AvatarFallback, AvatarImage } from '@/components/ui/avatar';
@@ -19,6 +19,7 @@ interface WhosSkatingProps {
 }
 
 function SkaterCard({ pubkey, status, emoji }: { pubkey: string; status: string; emoji?: string }) {
+  const navigate = useNavigate();
   const { data: authorData, isLoading } = useAuthor(pubkey);
   const metadata = authorData?.metadata;
   const displayName = metadata?.name ?? genUserName(pubkey);
@@ -68,8 +69,10 @@ function SkaterCard({ pubkey, status, emoji }: { pubkey: string; status: string;
           onClick={(e) => {
             e.preventDefault();
             e.stopPropagation();
-            // Navigate to DM
-            window.location.href = `/messages/${npub}`;
+            // Client-side navigation (HashRouter). Using window.location.href
+            // here caused a full reload to a non-hash path the router couldn't
+            // match — a broken jump. useNavigate keeps it in-app and instant.
+            navigate(`/messages/${npub}`);
           }}
         >
           <MessageCircle className="h-4 w-4" />

src/pages/StashPage.tsx

@@ -733,7 +733,7 @@ export default function StashPage() {
               <AlertTriangle className="h-12 w-12 mx-auto mb-4 text-yellow-500" />
               <h2 className="text-2xl font-black uppercase text-white mb-3">Encryption Required</h2>
               <p className="text-gray-300 mb-6 max-w-md mx-auto">Your Stash is encrypted for privacy. Please use a signer that supports NIP-44 encryption (like Alby, nos2x, or Amber).</p>
-              <Button variant="outline" onClick={() => window.location.href = '/signers'}>Learn About Signers</Button>
+              <Button variant="outline" asChild><Link to="/signers">Learn About Signers</Link></Button>
             </CardContent>
           </Card>
         </div>