feat(release-notes): Add 'Notify' button for admins

- Admin can send notifications about any release to all users
- Button visible only for logged-in admins
- Extracts first 3 highlights from 'new' section
- Shows confirmation dialog before sending
- Visual feedback: disabled during send, green when done

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/release_notes.html

@@ -170,6 +170,33 @@
         text-align: center;
     }
 
+    .notify-btn {
+        background: var(--primary);
+        color: white;
+        border: none;
+        padding: 6px 12px;
+        border-radius: var(--radius);
+        font-size: var(--font-size-xs);
+        cursor: pointer;
+        display: inline-flex;
+        align-items: center;
+        gap: 4px;
+        transition: background 0.2s;
+    }
+
+    .notify-btn:hover {
+        background: var(--primary-dark, #1a56db);
+    }
+
+    .notify-btn:disabled {
+        background: var(--text-secondary);
+        cursor: not-allowed;
+    }
+
+    .notify-btn.sent {
+        background: #16a34a;
+    }
+
     .stat-item h3 {
         font-size: var(--font-size-3xl);
         font-weight: 700;
@@ -233,7 +260,14 @@
                             {% endfor %}
                         </div>
                     </div>
-                    <div class="release-date">{{ release.date }}</div>
+                    <div style="display: flex; align-items: center; gap: 8px;">
+                        <div class="release-date">{{ release.date }}</div>
+                        {% if current_user.is_authenticated and current_user.is_admin %}
+                        <button class="notify-btn" onclick="notifyRelease('{{ release.version }}', this)" title="Wyślij powiadomienia o tej wersji">
+                            🔔 Powiadom
+                        </button>
+                        {% endif %}
+                    </div>
                 </div>
 
                 <div class="release-changes">
@@ -287,3 +321,53 @@
     </div>
 </div>
 {% endblock %}
+
+{% block extra_js %}
+{% if current_user.is_authenticated and current_user.is_admin %}
+function notifyRelease(version, btn) {
+    if (!confirm('Czy na pewno chcesz wysłać powiadomienia o wersji ' + version + ' do wszystkich użytkowników?')) {
+        return;
+    }
+
+    btn.disabled = true;
+    btn.innerHTML = '⏳ Wysyłanie...';
+
+    // Get first 3 highlights from the release card
+    const card = btn.closest('.release-card');
+    const highlights = [];
+    const items = card.querySelectorAll('.change-category.new .change-list li');
+    items.forEach((item, i) => {
+        if (i < 3) highlights.push(item.textContent.trim());
+    });
+
+    fetch('/admin/notify-release', {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/json',
+            'X-CSRFToken': '{{ csrf_token() }}'
+        },
+        body: JSON.stringify({
+            version: version,
+            highlights: highlights
+        })
+    })
+    .then(response => response.json())
+    .then(data => {
+        if (data.success) {
+            btn.innerHTML = '✅ Wysłano';
+            btn.classList.add('sent');
+            alert(data.message);
+        } else {
+            btn.innerHTML = '❌ Błąd';
+            btn.disabled = false;
+            alert('Błąd: ' + data.error);
+        }
+    })
+    .catch(error => {
+        btn.innerHTML = '❌ Błąd';
+        btn.disabled = false;
+        alert('Błąd połączenia: ' + error);
+    });
+}
+{% endif %}
+{% endblock %}