Replace CSV export with PDF report generation

- Add QuestPDF library for professional PDF generation
- Create PdfReportService with formatted table layout
- Export includes score (color-coded), verified employers, gaps, and flags
- Report has header, footer with page numbers, and alternating row colors

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

src/TrueCV.Web/TrueCV.Web.csproj

@@ -11,6 +11,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore" Version="8.0.*" />
+    <PackageReference Include="QuestPDF" Version="2025.12.3" />
     <PackageReference Include="Serilog.AspNetCore" Version="10.0.0" />
   </ItemGroup>