PWA: installable app (web/win/android/ios) + download/help page + push notifications

- manifest.webmanifest + service worker (offline shell + push + notificationclick) + PNG icons (192/512/apple) + iOS meta + SW registration → installable everywhere
- /Download page: per-OS install help (web/windows/android/ios), install button (beforeinstallprompt), 'enable notifications' flow, usage guide, Bazaar/TWA note; nav + footer links
- Web Push foundation: WebPushSubscription entity + /push/subscribe (stores), VAPID + push settings in /Admin/Settings, on-device local notification; server broadcast documented (WebPush via Nexus)
- docs/PWA-TWA.md: VAPID keygen, server-push wiring, Bubblewrap→Cafe Bazaar + assetlinks steps
- Verified: manifest/sw/icons served, download page, subscribe stores (200), layout wired

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/JobsMedical.Web/Pages/Admin/Settings.cshtml

@@ -142,6 +142,28 @@
             <p class="muted" style="font-size:12px; margin:4px 0 0;">برای انتخاب موقعیت روی نقشه در فرم ثبت مرکز. بدون کلید، فقط دکمه «موقعیت فعلی من» نمایش داده می‌شود.</p>
         </div>
 
+        <hr style="border:none; border-top:1px solid var(--line); margin:18px 0;" />
+        <h3 style="margin-top:0;">اعلان‌ها (Web Push / PWA)</h3>
+        <div class="filter-group">
+            <label style="display:flex; align-items:center; gap:8px; font-weight:700;">
+                <input type="checkbox" name="PushEnabled" value="true" style="width:auto;" checked="@Model.PushEnabled" />
+                فعال‌سازی اشتراک اعلان مرورگری
+            </label>
+        </div>
+        <div class="filter-group">
+            <label>VAPID Public Key</label>
+            <input type="text" name="VapidPublicKey" value="@Model.VapidPublicKey" dir="ltr" />
+        </div>
+        <div class="filter-group">
+            <label>VAPID Private Key</label>
+            <input type="password" name="VapidPrivateKey" value="@Model.VapidPrivateKey" dir="ltr" />
+        </div>
+        <div class="filter-group">
+            <label>VAPID Subject</label>
+            <input type="text" name="VapidSubject" value="@Model.VapidSubject" dir="ltr" placeholder="mailto:admin@hamkadr.ir" />
+        </div>
+        <p class="muted" style="font-size:12px;">جفت‌کلید VAPID را یک‌بار بساز (web-push). بدون آن، اعلان محلی روی دستگاه کار می‌کند ولی ارسال از سرور نیاز به کلید دارد.</p>
+
         <button type="submit" class="btn btn-accent btn-block btn-lg">ذخیره تنظیمات</button>
     </form>
 </div>

src/JobsMedical.Web/Pages/Admin/Settings.cshtml.cs

@@ -37,6 +37,10 @@ public class SettingsModel : PageModel
     [BindProperty] public string? SmsTemplate { get; set; }
     [BindProperty] public string? SmsSender { get; set; }
     [BindProperty] public string? NeshanMapKey { get; set; }
+    [BindProperty] public bool PushEnabled { get; set; }
+    [BindProperty] public string? VapidPublicKey { get; set; }
+    [BindProperty] public string? VapidPrivateKey { get; set; }
+    [BindProperty] public string? VapidSubject { get; set; }
     [TempData] public string? Saved { get; set; }
 
     public async Task OnGetAsync()
@@ -66,6 +70,10 @@ public class SettingsModel : PageModel
         SmsTemplate = s.SmsTemplate;
         SmsSender = s.SmsSender;
         NeshanMapKey = s.NeshanMapKey;
+        PushEnabled = s.PushEnabled;
+        VapidPublicKey = s.VapidPublicKey;
+        VapidPrivateKey = s.VapidPrivateKey;
+        VapidSubject = s.VapidSubject;
     }
 
     public async Task<IActionResult> OnPostAsync()
@@ -96,6 +104,10 @@ public class SettingsModel : PageModel
             SmsTemplate = SmsTemplate,
             SmsSender = SmsSender,
             NeshanMapKey = NeshanMapKey,
+            PushEnabled = PushEnabled,
+            VapidPublicKey = VapidPublicKey,
+            VapidPrivateKey = VapidPrivateKey,
+            VapidSubject = VapidSubject,
         });
         Saved = "تنظیمات ذخیره شد.";
         return RedirectToPage();