feat: Add material dimensions with typed properties

Implement TPH inheritance for material dimensions:
- MaterialShape enum with display names and parsing
- MaterialType enum (Steel, Aluminum, Stainless, etc.)
- MaterialDimensions base class with derived types per shape
- Auto-generate size strings from typed dimensions
- SortOrder field for numeric dimension sorting

Each shape has specific dimension properties:
- RoundBar: Diameter
- RoundTube: OuterDiameter, Wall
- FlatBar: Width, Thickness
- SquareBar/Tube: Size, Wall
- RectangularTube: Width, Height, Wall
- Angle: Leg1, Leg2, Thickness
- Channel: Height, Flange, Web
- IBeam: Height, WeightPerFoot
- Pipe: NominalSize, Wall, Schedule

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CutList.Web/Migrations/20260205012737_AddMaterialDimensions.cs

@@ -0,0 +1,96 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace CutList.Web.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddMaterialDimensions : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "MaterialDimensions",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "int", nullable: false)
+                        .Annotation("SqlServer:Identity", "1, 1"),
+                    MaterialId = table.Column<int>(type: "int", nullable: false),
+                    DimensionType = table.Column<string>(type: "nvarchar(21)", maxLength: 21, nullable: false),
+                    Leg1 = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Leg2 = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Thickness = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Height = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Flange = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Web = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Width = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    WeightPerFoot = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    NominalSize = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Wall = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Schedule = table.Column<string>(type: "nvarchar(20)", maxLength: 20, nullable: true),
+                    Diameter = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    OuterDiameter = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true),
+                    Size = table.Column<decimal>(type: "decimal(10,4)", precision: 10, scale: 4, nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_MaterialDimensions", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_MaterialDimensions_Materials_MaterialId",
+                        column: x => x.MaterialId,
+                        principalTable: "Materials",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_Diameter",
+                table: "MaterialDimensions",
+                column: "Diameter");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_Height",
+                table: "MaterialDimensions",
+                column: "Height");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_Leg1",
+                table: "MaterialDimensions",
+                column: "Leg1");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_MaterialId",
+                table: "MaterialDimensions",
+                column: "MaterialId",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_NominalSize",
+                table: "MaterialDimensions",
+                column: "NominalSize");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_OuterDiameter",
+                table: "MaterialDimensions",
+                column: "OuterDiameter");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_Size",
+                table: "MaterialDimensions",
+                column: "Size");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_MaterialDimensions_Width",
+                table: "MaterialDimensions",
+                column: "Width");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "MaterialDimensions");
+        }
+    }
+}