[PM-30920] Server changes to encrypt send access email list (#6867)

* models, entity, and stored procs updated to work with EmailHashes with migrations

* configure data protection for EmailHashes

* update SendAuthenticationQuery to use EmailHashes and perform validation

* respond to Claude's comments and update tests

* fix send.sql alignment

Co-authored-by: mkincaid-bw <mkincaid@bitwarden.com>

---------

Co-authored-by: Alex Dragovich <46065570+itsadrago@users.noreply.github.com>
Co-authored-by: mkincaid-bw <mkincaid@bitwarden.com>

util/MySqlMigrations/Migrations/20260117234040_2026-01-17_00_Send_EmailHashes.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bit.MySqlMigrations.Migrations;
+
+/// <inheritdoc />
+public partial class _20260117_00_Send_EmailHashes : Migration
+{
+    /// <inheritdoc />
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.AddColumn<string>(
+            name: "EmailHashes",
+            table: "Send",
+            type: "varchar(4000)",
+            maxLength: 4000,
+            nullable: true)
+            .Annotation("MySql:CharSet", "utf8mb4");
+    }
+
+    /// <inheritdoc />
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.DropColumn(
+            name: "EmailHashes",
+            table: "Send");
+    }
+}

util/MySqlMigrations/Migrations/DatabaseContextModelSnapshot.cs

@@ -1689,6 +1689,10 @@ namespace Bit.MySqlMigrations.Migrations
                     b.Property<bool>("Disabled")
                         .HasColumnType("tinyint(1)");
 
+                    b.Property<string>("EmailHashes")
+                        .HasMaxLength(4000)
+                        .HasColumnType("varchar(4000)");
+
                     b.Property<string>("Emails")
                         .HasMaxLength(4000)
                         .HasColumnType("varchar(4000)");