Notify matching users when a new shift/job is posted (in-app notifications)

- Notification entity + NotificationService: on publish, notify users whose saved prefs match the listing (role/city/+shift type); users with no preference aren't spammed
- Wired into PostShift, PostJob, and Admin Review publish
- 🔔 bell with unread count in the header (@inject) + /Me/Notifications page (mark-all-read on open)
- Reliable in-app delivery (works in Iran without FCM); Web Push can ride the same records later
- Verified: employee pref → employer posts matching shift → employee bell=۱ + 'شیفت جدید: پزشک عمومی'

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

src/JobsMedical.Web/Migrations/AppDbContextModelSnapshot.cs

@@ -430,6 +430,43 @@ namespace JobsMedical.Web.Migrations
                     b.ToTable("JobOpenings");
                 });
 
+            modelBuilder.Entity("JobsMedical.Web.Models.Notification", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Body")
+                        .HasMaxLength(500)
+                        .HasColumnType("character varying(500)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<bool>("IsRead")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("Url")
+                        .HasMaxLength(300)
+                        .HasColumnType("character varying(300)");
+
+                    b.Property<int>("UserId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "IsRead", "CreatedAt");
+
+                    b.ToTable("Notifications");
+                });
+
             modelBuilder.Entity("JobsMedical.Web.Models.RawListing", b =>
                 {
                     b.Property<int>("Id")
@@ -843,6 +880,17 @@ namespace JobsMedical.Web.Migrations
                     b.Navigation("Role");
                 });
 
+            modelBuilder.Entity("JobsMedical.Web.Models.Notification", b =>
+                {
+                    b.HasOne("JobsMedical.Web.Models.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
             modelBuilder.Entity("JobsMedical.Web.Models.RawListing", b =>
                 {
                     b.HasOne("JobsMedical.Web.Models.Shift", "LinkedShift")