Add notification entities, DbContext config, and migration

Creates MemberChannelBinding, LineBindingCode, MessagingGroup, and NotificationLog
entities under ROLAC.API.Entities.Notifications; wires DbSets and fluent config into
AppDbContext; generates EF migration AddNotifications creating the four tables.

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

API/ROLAC.API/Data/AppDbContext.cs

@@ -2,6 +2,7 @@ using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;
 using ROLAC.API.Data.Logging;
 using ROLAC.API.Entities;
+using ROLAC.API.Entities.Notifications;
 
 namespace ROLAC.API.Data;
 
@@ -26,6 +27,11 @@ public class AppDbContext : IdentityDbContext<AppUser, AppRole, string>
     public DbSet<MealAttendance>   MealAttendances   => Set<MealAttendance>();
     public DbSet<RolePermission>   RolePermissions   => Set<RolePermission>();
 
+    public DbSet<MemberChannelBinding> MemberChannelBindings => Set<MemberChannelBinding>();
+    public DbSet<LineBindingCode>      LineBindingCodes      => Set<LineBindingCode>();
+    public DbSet<MessagingGroup>       MessagingGroups       => Set<MessagingGroup>();
+    public DbSet<NotificationLog>      NotificationLogs      => Set<NotificationLog>();
+
     protected override void OnModelCreating(ModelBuilder builder)
     {
         base.OnModelCreating(builder);
@@ -326,6 +332,49 @@ public class AppDbContext : IdentityDbContext<AppUser, AppRole, string>
             entity.HasIndex(e => new { e.Year, e.Month }).IsUnique();
         });
 
+        // ── Notifications (email + Line) ─────────────────────────────────────
+        builder.Entity<MemberChannelBinding>(entity =>
+        {
+            entity.Property(e => e.Channel).HasMaxLength(20).IsRequired();
+            entity.Property(e => e.ExternalId).HasMaxLength(100).IsRequired();
+            entity.HasIndex(e => new { e.MemberId, e.Channel }).IsUnique();
+            entity.HasIndex(e => new { e.Channel, e.ExternalId }).IsUnique();
+            entity.HasOne(e => e.Member).WithMany()
+                  .HasForeignKey(e => e.MemberId).OnDelete(DeleteBehavior.Cascade);
+        });
+
+        builder.Entity<LineBindingCode>(entity =>
+        {
+            entity.Property(e => e.Code).HasMaxLength(20).IsRequired();
+            entity.HasIndex(e => e.Code);
+            entity.HasOne(e => e.Member).WithMany()
+                  .HasForeignKey(e => e.MemberId).OnDelete(DeleteBehavior.Cascade);
+        });
+
+        builder.Entity<MessagingGroup>(entity =>
+        {
+            entity.Property(e => e.Channel).HasMaxLength(20).IsRequired();
+            entity.Property(e => e.ExternalId).HasMaxLength(100).IsRequired();
+            entity.Property(e => e.Name).HasMaxLength(200);
+            entity.HasIndex(e => new { e.Channel, e.ExternalId }).IsUnique();
+        });
+
+        builder.Entity<NotificationLog>(entity =>
+        {
+            entity.Property(e => e.Channel).HasMaxLength(20).IsRequired();
+            entity.Property(e => e.TargetType).HasMaxLength(20).IsRequired();
+            entity.Property(e => e.TargetExternalId).HasMaxLength(200).IsRequired();
+            entity.Property(e => e.Subject).HasMaxLength(300);
+            entity.Property(e => e.Status).HasMaxLength(20).IsRequired();
+            entity.Property(e => e.SentByUserId).HasMaxLength(450).IsRequired();
+            entity.HasIndex(e => e.SentAt);
+            entity.HasIndex(e => e.Channel);
+            entity.HasOne(e => e.Member).WithMany()
+                  .HasForeignKey(e => e.MemberId).OnDelete(DeleteBehavior.SetNull);
+            entity.HasOne(e => e.MessagingGroup).WithMany()
+                  .HasForeignKey(e => e.MessagingGroupId).OnDelete(DeleteBehavior.SetNull);
+        });
+
         // ── SystemLog / AuditLog (append-only) ───────────────────────────────
         // Mapped here for SCHEMA only — there are deliberately no DbSets on this
         // context, so business code can't write logs through the audited context.

API/ROLAC.API/Entities/Notifications/LineBindingCode.cs

@@ -0,0 +1,14 @@
+using ROLAC.API.Entities;
+
+namespace ROLAC.API.Entities.Notifications;
+
+/// <summary>A short-lived code a member types to the Line bot to complete account binding.</summary>
+public class LineBindingCode
+{
+    public int       Id         { get; set; }
+    public string    Code       { get; set; } = null!;
+    public int       MemberId   { get; set; }
+    public Member?   Member     { get; set; }
+    public DateTime  ExpiresAt  { get; set; }
+    public DateTime? ConsumedAt { get; set; }            // null = unused
+}

API/ROLAC.API/Entities/Notifications/MemberChannelBinding.cs

@@ -0,0 +1,17 @@
+using ROLAC.API.Entities;
+
+namespace ROLAC.API.Entities.Notifications;
+
+/// <summary>
+/// Binds a member to an external channel account (e.g. a Line userId). Separate table so future
+/// channels don't require changes to Member.
+/// </summary>
+public class MemberChannelBinding
+{
+    public int      Id         { get; set; }
+    public int      MemberId   { get; set; }
+    public Member?  Member     { get; set; }
+    public string   Channel    { get; set; } = null!;   // "line"
+    public string   ExternalId { get; set; } = null!;   // Line userId
+    public DateTime BoundAt    { get; set; }
+}

API/ROLAC.API/Entities/Notifications/MessagingGroup.cs

@@ -0,0 +1,12 @@
+namespace ROLAC.API.Entities.Notifications;
+
+/// <summary>A Line group the bot was added to. Named by an admin after the join event.</summary>
+public class MessagingGroup
+{
+    public int      Id           { get; set; }
+    public string   Channel      { get; set; } = null!;  // "line"
+    public string   ExternalId   { get; set; } = null!;  // Line groupId
+    public string?  Name         { get; set; }
+    public bool     IsActive     { get; set; } = true;
+    public DateTime RegisteredAt { get; set; }
+}

API/ROLAC.API/Entities/Notifications/NotificationLog.cs

@@ -0,0 +1,22 @@
+using ROLAC.API.Entities;
+
+namespace ROLAC.API.Entities.Notifications;
+
+/// <summary>An append-only audit row for every email or Line send (success or failure).</summary>
+public class NotificationLog
+{
+    public long     Id               { get; set; }
+    public string   Channel          { get; set; } = null!;  // "email" | "line"
+    public string   TargetType       { get; set; } = null!;  // "email" | "user" | "group"
+    public string   TargetExternalId { get; set; } = null!;  // email address OR Line id
+    public string?  Subject          { get; set; }            // email only
+    public int?     MemberId         { get; set; }
+    public Member?  Member           { get; set; }
+    public int?     MessagingGroupId { get; set; }
+    public MessagingGroup? MessagingGroup { get; set; }
+    public string   Body             { get; set; } = null!;
+    public string   Status           { get; set; } = null!;  // "sent" | "failed"
+    public string?  Error            { get; set; }
+    public string   SentByUserId     { get; set; } = null!;
+    public DateTime SentAt           { get; set; }
+}

API/ROLAC.API/Migrations/20260624020251_AddNotifications.cs

@@ -0,0 +1,176 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace ROLAC.API.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddNotifications : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "LineBindingCodes",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    Code = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    MemberId = table.Column<int>(type: "integer", nullable: false),
+                    ExpiresAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: false),
+                    ConsumedAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_LineBindingCodes", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_LineBindingCodes_Members_MemberId",
+                        column: x => x.MemberId,
+                        principalTable: "Members",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "MemberChannelBindings",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    MemberId = table.Column<int>(type: "integer", nullable: false),
+                    Channel = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    ExternalId = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: false),
+                    BoundAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_MemberChannelBindings", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_MemberChannelBindings_Members_MemberId",
+                        column: x => x.MemberId,
+                        principalTable: "Members",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "MessagingGroups",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    Channel = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    ExternalId = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: false),
+                    Name = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: true),
+                    IsActive = table.Column<bool>(type: "boolean", nullable: false),
+                    RegisteredAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_MessagingGroups", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "NotificationLogs",
+                columns: table => new
+                {
+                    Id = table.Column<long>(type: "bigint", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    Channel = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    TargetType = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    TargetExternalId = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: false),
+                    Subject = table.Column<string>(type: "character varying(300)", maxLength: 300, nullable: true),
+                    MemberId = table.Column<int>(type: "integer", nullable: true),
+                    MessagingGroupId = table.Column<int>(type: "integer", nullable: true),
+                    Body = table.Column<string>(type: "text", nullable: false),
+                    Status = table.Column<string>(type: "character varying(20)", maxLength: 20, nullable: false),
+                    Error = table.Column<string>(type: "text", nullable: true),
+                    SentByUserId = table.Column<string>(type: "character varying(450)", maxLength: 450, nullable: false),
+                    SentAt = table.Column<DateTime>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_NotificationLogs", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_NotificationLogs_Members_MemberId",
+                        column: x => x.MemberId,
+                        principalTable: "Members",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.SetNull);
+                    table.ForeignKey(
+                        name: "FK_NotificationLogs_MessagingGroups_MessagingGroupId",
+                        column: x => x.MessagingGroupId,
+                        principalTable: "MessagingGroups",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.SetNull);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LineBindingCodes_Code",
+                table: "LineBindingCodes",
+                column: "Code");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LineBindingCodes_MemberId",
+                table: "LineBindingCodes",
+                column: "MemberId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MemberChannelBindings_Channel_ExternalId",
+                table: "MemberChannelBindings",
+                columns: new[] { "Channel", "ExternalId" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MemberChannelBindings_MemberId_Channel",
+                table: "MemberChannelBindings",
+                columns: new[] { "MemberId", "Channel" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MessagingGroups_Channel_ExternalId",
+                table: "MessagingGroups",
+                columns: new[] { "Channel", "ExternalId" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_NotificationLogs_Channel",
+                table: "NotificationLogs",
+                column: "Channel");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_NotificationLogs_MemberId",
+                table: "NotificationLogs",
+                column: "MemberId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_NotificationLogs_MessagingGroupId",
+                table: "NotificationLogs",
+                column: "MessagingGroupId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_NotificationLogs_SentAt",
+                table: "NotificationLogs",
+                column: "SentAt");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "LineBindingCodes");
+
+            migrationBuilder.DropTable(
+                name: "MemberChannelBindings");
+
+            migrationBuilder.DropTable(
+                name: "NotificationLogs");
+
+            migrationBuilder.DropTable(
+                name: "MessagingGroups");
+        }
+    }
+}

API/ROLAC.API/Migrations/AppDbContextModelSnapshot.cs

@@ -1323,6 +1323,174 @@ namespace ROLAC.API.Migrations
                     b.ToTable("MonthlyStatements");
                 });
 
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.LineBindingCode", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("Code")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<DateTime?>("ConsumedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTime>("ExpiresAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<int>("MemberId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Code");
+
+                    b.HasIndex("MemberId");
+
+                    b.ToTable("LineBindingCodes");
+                });
+
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.MemberChannelBinding", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<DateTime>("BoundAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Channel")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<string>("ExternalId")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<int>("MemberId")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Channel", "ExternalId")
+                        .IsUnique();
+
+                    b.HasIndex("MemberId", "Channel")
+                        .IsUnique();
+
+                    b.ToTable("MemberChannelBindings");
+                });
+
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.MessagingGroup", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("Channel")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<string>("ExternalId")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<DateTime>("RegisteredAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Channel", "ExternalId")
+                        .IsUnique();
+
+                    b.ToTable("MessagingGroups");
+                });
+
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.NotificationLog", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("bigint");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<long>("Id"));
+
+                    b.Property<string>("Body")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Channel")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<string>("Error")
+                        .HasColumnType("text");
+
+                    b.Property<int?>("MemberId")
+                        .HasColumnType("integer");
+
+                    b.Property<int?>("MessagingGroupId")
+                        .HasColumnType("integer");
+
+                    b.Property<DateTime>("SentAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("SentByUserId")
+                        .IsRequired()
+                        .HasMaxLength(450)
+                        .HasColumnType("character varying(450)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.Property<string>("Subject")
+                        .HasMaxLength(300)
+                        .HasColumnType("character varying(300)");
+
+                    b.Property<string>("TargetExternalId")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("TargetType")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("character varying(20)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Channel");
+
+                    b.HasIndex("MemberId");
+
+                    b.HasIndex("MessagingGroupId");
+
+                    b.HasIndex("SentAt");
+
+                    b.ToTable("NotificationLogs");
+                });
+
             modelBuilder.Entity("ROLAC.API.Entities.OfferingSession", b =>
                 {
                     b.Property<int>("Id")
@@ -1645,6 +1813,45 @@ namespace ROLAC.API.Migrations
                     b.Navigation("FamilyUnit");
                 });
 
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.LineBindingCode", b =>
+                {
+                    b.HasOne("ROLAC.API.Entities.Member", "Member")
+                        .WithMany()
+                        .HasForeignKey("MemberId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Member");
+                });
+
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.MemberChannelBinding", b =>
+                {
+                    b.HasOne("ROLAC.API.Entities.Member", "Member")
+                        .WithMany()
+                        .HasForeignKey("MemberId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Member");
+                });
+
+            modelBuilder.Entity("ROLAC.API.Entities.Notifications.NotificationLog", b =>
+                {
+                    b.HasOne("ROLAC.API.Entities.Member", "Member")
+                        .WithMany()
+                        .HasForeignKey("MemberId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("ROLAC.API.Entities.Notifications.MessagingGroup", "MessagingGroup")
+                        .WithMany()
+                        .HasForeignKey("MessagingGroupId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("Member");
+
+                    b.Navigation("MessagingGroup");
+                });
+
             modelBuilder.Entity("ROLAC.API.Entities.RefreshToken", b =>
                 {
                     b.HasOne("ROLAC.API.Entities.AppUser", "User")