feat: Add SHA256 checksum generation to Windows build script

- Automatically generate checksum file after building exe
- Checksum saved as WebDropBridge.exe.sha256
- Required for package uploads
- Also increase upload timeout to 600s for large files

build/scripts/upload_to_packages.ps1

@@ -103,7 +103,9 @@ try {
         -Method PUT `
         -Headers $headers `
         -InFile $ExePath `
-        -ContentType "application/octet-stream"
+        -ContentType "application/octet-stream" `
+        -TimeoutSec 600 `
+        -ErrorAction Stop
     
     Write-Host "[OK] Executable uploaded successfully" -ForegroundColor Green
 }