feat: add local database and file export infrastructure

Add EF Core DbContext with ExportRecord and BomItem entities for
tracking export history locally. Add FileExportService for saving
DXF and PDF files to a configurable output folder.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ExportDXF/Data/ExportDxfDbContext.cs

@@ -0,0 +1,61 @@
+using ExportDXF.Models;
+using Microsoft.EntityFrameworkCore;
+using System.Configuration;
+
+namespace ExportDXF.Data
+{
+    public class ExportDxfDbContext : DbContext
+    {
+        public DbSet<ExportRecord> ExportRecords { get; set; }
+        public DbSet<BomItem> BomItems { get; set; }
+
+        public ExportDxfDbContext() : base()
+        {
+        }
+
+        public ExportDxfDbContext(DbContextOptions<ExportDxfDbContext> options) : base(options)
+        {
+        }
+
+        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+        {
+            if (!optionsBuilder.IsConfigured)
+            {
+                var connectionString = ConfigurationManager.ConnectionStrings["ExportDxfDb"]?.ConnectionString
+                    ?? "Server=localhost;Database=ExportDxfDb;Trusted_Connection=True;TrustServerCertificate=True;";
+                optionsBuilder.UseSqlServer(connectionString);
+            }
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            base.OnModelCreating(modelBuilder);
+
+            modelBuilder.Entity<ExportRecord>(entity =>
+            {
+                entity.HasKey(e => e.Id);
+                entity.Property(e => e.DrawingNumber).HasMaxLength(100);
+                entity.Property(e => e.SourceFilePath).HasMaxLength(500);
+                entity.Property(e => e.OutputFolder).HasMaxLength(500);
+                entity.Property(e => e.ExportedBy).HasMaxLength(100);
+
+                entity.HasMany(e => e.BomItems)
+                      .WithOne(b => b.ExportRecord)
+                      .HasForeignKey(b => b.ExportRecordId)
+                      .OnDelete(DeleteBehavior.Cascade);
+            });
+
+            modelBuilder.Entity<BomItem>(entity =>
+            {
+                entity.HasKey(e => e.ID);
+                entity.Property(e => e.ItemNo).HasMaxLength(50);
+                entity.Property(e => e.PartNo).HasMaxLength(100);
+                entity.Property(e => e.Description).HasMaxLength(500);
+                entity.Property(e => e.PartName).HasMaxLength(200);
+                entity.Property(e => e.ConfigurationName).HasMaxLength(100);
+                entity.Property(e => e.Material).HasMaxLength(100);
+                entity.Property(e => e.CutTemplateName).HasMaxLength(100);
+            });
+        }
+    }
+}

ExportDXF/Models/ExportRecord.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+
+namespace ExportDXF.Models
+{
+    public class ExportRecord
+    {
+        public int Id { get; set; }
+        public string DrawingNumber { get; set; }
+        public string SourceFilePath { get; set; }
+        public string OutputFolder { get; set; }
+        public DateTime ExportedAt { get; set; }
+        public string ExportedBy { get; set; }
+
+        public virtual ICollection<BomItem> BomItems { get; set; } = new List<BomItem>();
+    }
+}

ExportDXF/Services/FileExportService.cs

@@ -0,0 +1,72 @@
+using System;
+using System.IO;
+
+namespace ExportDXF.Services
+{
+    public interface IFileExportService
+    {
+        string OutputFolder { get; }
+        string SaveDxfFile(string sourcePath, string drawingNumber, string itemNo);
+        string SavePdfFile(string sourcePath, string drawingNumber);
+        void EnsureOutputFolderExists();
+    }
+
+    public class FileExportService : IFileExportService
+    {
+        public string OutputFolder { get; }
+
+        public FileExportService(string outputFolder)
+        {
+            OutputFolder = outputFolder ?? throw new ArgumentNullException(nameof(outputFolder));
+            EnsureOutputFolderExists();
+        }
+
+        public void EnsureOutputFolderExists()
+        {
+            if (!Directory.Exists(OutputFolder))
+            {
+                Directory.CreateDirectory(OutputFolder);
+            }
+        }
+
+        public string SaveDxfFile(string sourcePath, string drawingNumber, string itemNo)
+        {
+            if (string.IsNullOrEmpty(sourcePath))
+                throw new ArgumentNullException(nameof(sourcePath));
+
+            var fileName = !string.IsNullOrEmpty(drawingNumber) && !string.IsNullOrEmpty(itemNo)
+                ? $"{drawingNumber} PT{itemNo}.dxf"
+                : Path.GetFileName(sourcePath);
+
+            var destPath = Path.Combine(OutputFolder, fileName);
+
+            // If source and dest are the same, skip copy
+            if (!string.Equals(sourcePath, destPath, StringComparison.OrdinalIgnoreCase))
+            {
+                File.Copy(sourcePath, destPath, overwrite: true);
+            }
+
+            return destPath;
+        }
+
+        public string SavePdfFile(string sourcePath, string drawingNumber)
+        {
+            if (string.IsNullOrEmpty(sourcePath))
+                throw new ArgumentNullException(nameof(sourcePath));
+
+            var fileName = !string.IsNullOrEmpty(drawingNumber)
+                ? $"{drawingNumber}.pdf"
+                : Path.GetFileName(sourcePath);
+
+            var destPath = Path.Combine(OutputFolder, fileName);
+
+            // If source and dest are the same, skip copy
+            if (!string.Equals(sourcePath, destPath, StringComparison.OrdinalIgnoreCase))
+            {
+                File.Copy(sourcePath, destPath, overwrite: true);
+            }
+
+            return destPath;
+        }
+    }
+}