refactor: 프로젝트명 DB720Flasher → FirmwareFlasher

폴더·csproj·어셈블리명·RootNamespace·코드 namespace·x:Class·app.manifest 전부 변경.
빌드 결과가 네이티브로 FirmwareFlasher.exe 로 나온다(dist 수동 리네임 불필요).
README 빌드/구조 경로도 갱신. 모델명 "DB720"은 그대로 유지.

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

FirmwareFlasher/FirmwareFlasher.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>FirmwareFlasher</RootNamespace>
+    <AssemblyName>FirmwareFlasher</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>