Initial commit: 펌웨어 플래시 도구 (WPF) + 기존 PowerShell 키트

- DB720Flasher: WPF .NET 9 GUI 플래셔
  - 멀티모델 프로파일(flash.json + 빌트인 DB720/DB402S/DB400S/DB400Q/DB300eM)
  - 포트 자동감지(JTAG 우선, 유령 포트 자동 회피), esptool v5 동봉
- flash_app.ps1 / flash_full.ps1 / list_ports.ps1: 기존 PowerShell 키트
- profiles/: 모델별 flash.json 템플릿
- firmware/flash.json: DB720 모델 설정 (서명 실펌웨어 .bin 은 repo 제외)

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

DB720Flasher/DB720Flasher.csproj

@@ -0,0 +1,26 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net9.0-windows</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <UseWPF>true</UseWPF>
+    <RootNamespace>DB720Flasher</RootNamespace>
+    <AssemblyName>DB720Flasher</AssemblyName>
+    <Version>1.0.0</Version>
+    <ApplicationManifest>app.manifest</ApplicationManifest>
+    <SatelliteResourceLanguages>en</SatelliteResourceLanguages>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.Management" Version="9.0.0" />
+    <PackageReference Include="System.IO.Ports" Version="9.0.0" />
+  </ItemGroup>
+
+  <!-- 동봉 자산: firmware\ 와 tools\esptool\ 를 빌드 출력으로 복사 -->
+  <ItemGroup>
+    <None Include="tools\**\*" CopyToOutputDirectory="PreserveNewest" LinkBase="tools\" />
+  </ItemGroup>
+
+</Project>