feat(02-01): create HeaderBar component with brand, Bell placeholder, avatar trigger

- Sticky header with bg-background/95 backdrop-blur and border-b
- WulfMark + Pulse wordmark linked to /mobile/dashboard
- Bell icon placeholder (aria-label=Notifications, empty onClick per SHELL-03)
- Avatar circle (h-7 w-7) triggers drawer via onAvatarClick prop
- pt-safe applied for notch/dynamic-island clearance (PWA-04)
- Implements SHELL-02..04 requirements

components/mobile/HeaderBar.tsx

@@ -0,0 +1,72 @@
+'use client';
+
+/* HeaderBar — phase 02 (SHELL-02..04).
+ *
+ * Sticky top bar inside the /mobile shell. Three slots:
+ *   left:  WulfMark + "Pulse" wordmark, linked to /mobile/dashboard
+ *   right: Bell icon button (placeholder, aria-label="Notifications")
+ *   right: compact avatar circle — opens the More drawer (parent owns state)
+ *
+ * No page title in the header — pages render their own H1. */
+
+import Link from 'next/link';
+import { Bell } from 'lucide-react';
+import { WulfMark } from '@/components/branding/wulf-mark';
+import { useSession } from '@/lib/auth-client';
+
+interface HeaderBarProps {
+  onAvatarClick: () => void;
+}
+
+export function HeaderBar({ onAvatarClick }: HeaderBarProps) {
+  const { data: session } = useSession();
+  const user = session?.user as
+    | { name?: string; email?: string }
+    | undefined;
+
+  const initials = (user?.name ?? user?.email ?? '?')
+    .split(/[\s@]/)
+    .filter(Boolean)
+    .slice(0, 2)
+    .map((p) => p[0]?.toUpperCase())
+    .join('');
+
+  return (
+    <header className="sticky top-0 z-30 bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/80 border-b pt-safe">
+      <div className="flex items-center justify-between px-4 h-14">
+        {/* Left: brand mark + wordmark, linked to /mobile/dashboard */}
+        <Link
+          href="/mobile/dashboard"
+          className="flex items-center gap-2 -ml-1 px-1 rounded-md hover:bg-accent/50 transition-colors"
+          aria-label="Pulse — go to Dashboard"
+        >
+          <WulfMark variant="mark" className="h-6 w-auto" />
+          <span className="font-bold text-base tracking-tight">Pulse</span>
+        </Link>
+
+        {/* Right: Bell placeholder, then avatar trigger */}
+        <div className="flex items-center gap-1">
+          <button
+            type="button"
+            onClick={() => { /* SHELL-03: placeholder — no menu, no badge */ }}
+            aria-label="Notifications"
+            className="inline-flex items-center justify-center h-9 w-9 rounded-md hover:bg-accent transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+          >
+            <Bell className="h-5 w-5" />
+          </button>
+
+          <button
+            type="button"
+            onClick={onAvatarClick}
+            aria-label="Open menu"
+            className="inline-flex items-center justify-center h-9 w-9 rounded-md hover:bg-accent transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+          >
+            <span className="inline-flex h-7 w-7 items-center justify-center rounded-full bg-primary/15 text-primary text-[11px] font-semibold">
+              {initials}
+            </span>
+          </button>
+        </div>
+      </div>
+    </header>
+  );
+}