Add per-user Like (پسندیدن) with a liked page and counts

Logged-in users can like a listing (job/shift/talent); dislike is removed per request — only likes.
- Like model (polymorphic by TargetType+TargetId) + EF migration; unique per (user, listing).
- POST /like toggles the like (auth required) and returns {liked, count}.
- Detail pages: the old ♡ Save / ✕ Dismiss buttons are replaced by a single heart Like button that
  shows the live count and toggles in place; clicking while logged out redirects to login.
- New «❤️ پسندیده‌ها» page (/Me/Liked) lists everything the user liked (open listings only), with a
  nav entry shown only when authenticated.

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

src/JobsMedical.Web/Pages/Shifts/Details.cshtml

@@ -135,16 +135,11 @@
                             data-contact-type="shift" data-contact-id="@s.Id">📞 اعلام تمایل و مشاهده راه ارتباطی</button>
                     <p class="muted center" style="font-size:12px; margin:8px 0;">با اعلام تمایل، اطلاعات تماس مرکز نمایش داده می‌شود.</p>
                 </div>
-                <div style="display:flex; gap:8px;">
-                    <form method="post" style="flex:1;">
-                        <button type="submit" asp-page-handler="Save" asp-route-id="@s.Id"
-                                class="btn btn-outline btn-block">♡ ذخیره</button>
-                    </form>
-                    <form method="post" style="flex:1;">
-                        <button type="submit" asp-page-handler="Dismiss" asp-route-id="@s.Id"
-                                class="btn btn-outline btn-block">✕ علاقه‌مند نیستم</button>
-                    </form>
-                </div>
+                <button type="button" class="btn @(Model.IsLiked ? "btn-accent" : "btn-outline") btn-block like-trigger"
+                        data-like-type="shift" data-like-id="@s.Id" data-liked="@(Model.IsLiked ? "true" : "false")">
+                    <span class="like-ico">@(Model.IsLiked ? "♥" : "♡")</span> پسندیدم
+                    <span class="like-count">@JalaliDate.ToPersianDigits(Model.LikeCount.ToString())</span>
+                </button>
                 @if (Model.Reported)
                 {
                     <p class="muted" style="font-size:12px; margin:8px 0 0;">✓ گزارش شما ثبت شد. متشکریم.</p>
@@ -212,9 +207,10 @@
 <div class="mobile-action-bar">
     <button type="button" class="btn btn-accent btn-lg cta-main contact-trigger"
             data-contact-type="shift" data-contact-id="@s.Id">📞 اعلام تمایل و مشاهده تماس</button>
-    <form method="post">
-        <button type="submit" asp-page-handler="Save" asp-route-id="@s.Id" class="btn btn-outline btn-lg" aria-label="ذخیره" title="ذخیره">♡</button>
-    </form>
+    <button type="button" class="btn @(Model.IsLiked ? "btn-accent" : "btn-outline") btn-lg like-trigger" aria-label="پسندیدن"
+            data-like-type="shift" data-like-id="@s.Id" data-liked="@(Model.IsLiked ? "true" : "false")">
+        <span class="like-ico">@(Model.IsLiked ? "♥" : "♡")</span> <span class="like-count">@JalaliDate.ToPersianDigits(Model.LikeCount.ToString())</span>
+    </button>
 </div>
 
 @if (!string.IsNullOrEmpty(Model.MapKey) && mapLat is not null)