fix(09.1-01): ProfileChannelsSection QR + subscribe link target company ntfy server

- Add NTFY_BASE const (NEXT_PUBLIC_NTFY_BASE_URL || 'https://ntfy.wulfconsulting.cloud') at module scope
- Subscribe link href and rendered text use NTFY_BASE instead of ntfy.sh
- QRCodeSVG value uses NTFY_BASE — ntfy.sh no longer referenced in file
- Add muted help line 'Topic must start with pulse-me-' between custom-topic Input and error paragraph

components/mobile/profile/ProfileChannelsSection.tsx

@@ -28,6 +28,12 @@ import { Button } from '@/components/ui/button';
 import { Label } from '@/components/ui/label';
 import { Separator } from '@/components/ui/separator';
 
+// Personal ntfy channels target the company ntfy instance. The fallback
+// matches the server-side default in personal-channels.ts / notify.ts so
+// the UI and the publish path stay aligned even when the env var is unset
+// in a dev shell (UAT-FIX-01).
+const NTFY_BASE = process.env.NEXT_PUBLIC_NTFY_BASE_URL || 'https://ntfy.wulfconsulting.cloud';
+
 // ── Types ────────────────────────────────────────────────────────────────────
 
 interface Channel {
@@ -279,12 +285,12 @@ export function ProfileChannelsSection() {
             /* State B — topic minted */
             <div className="space-y-3">
               <a
-                href={`https://ntfy.sh/${ntfyTopic}`}
+                href={`${NTFY_BASE}/${ntfyTopic}`}
                 target="_blank"
                 rel="noopener noreferrer"
                 className="text-primary text-sm underline break-all"
               >
-                {`https://ntfy.sh/${ntfyTopic}`}
+                {`${NTFY_BASE}/${ntfyTopic}`}
               </a>
 
               <div
@@ -292,7 +298,7 @@ export function ProfileChannelsSection() {
                 aria-label={`Subscribe to ${ntfyTopic} on ntfy`}
                 className="flex justify-center"
               >
-                <QRCodeSVG value={`https://ntfy.sh/${ntfyTopic}`} size={200} />
+                <QRCodeSVG value={`${NTFY_BASE}/${ntfyTopic}`} size={200} />
               </div>
 
               <p className="text-xs text-muted-foreground">
@@ -315,6 +321,9 @@ export function ProfileChannelsSection() {
                       setCustomTopicError(null);
                     }}
                   />
+                  <p className="text-xs text-muted-foreground">
+                    Topic must start with <code>pulse-me-</code>.
+                  </p>
                   {customTopicError && (
                     <p className="text-xs text-destructive">{customTopicError}</p>
                   )}