refactor: Switch from CI/CD runners to Forgejo Packages distribution

- Remove .forgejo/workflows/build.yml (not needed)
- Remove FORGEJO_CI_CD_SETUP.md (runner approach obsolete)
- Remove PHASE_3_3_CI_CD_SUMMARY.md (CI/CD approach replaced)
- Add upload_to_packages.ps1 (Windows upload script)
- Add upload_to_packages.sh (macOS upload script)
- Add FORGEJO_PACKAGES_SETUP.md (comprehensive guide)
- Update DEVELOPMENT_PLAN.md Phase 3.3

Rationale:
- Simpler: No runner installation needed
- More practical: Manual builds on local machines
- More flexible: Build when you want
- Same distribution hub: Forgejo Packages
- Same auto-update integration: UpdateManager queries API

Release workflow:
1. Build locally on Windows and macOS
2. Upload both to Forgejo Packages
3. Tag release: git tag v1.0.0
4. Users download from Packages page

build/scripts/upload_to_packages.ps1

@@ -0,0 +1,80 @@
+# Upload Windows Build to Forgejo Packages
+# Usage: .\upload_to_packages.ps1 -Version 1.0.0 -ForgejoToken $token
+
+param(
+    [Parameter(Mandatory=$true)]
+    [string]$Version,
+    
+    [Parameter(Mandatory=$true)]
+    [string]$ForgejoToken,
+    
+    [string]$ForgejoUrl = "https://git.him-tools.de",
+    [string]$Repo = "HIM-public/webdrop-bridge",
+    [string]$ExePath = "build\dist\windows\WebDropBridge.exe",
+    [string]$ChecksumPath = "build\dist\windows\WebDropBridge.exe.sha256"
+)
+
+$ErrorActionPreference = "Stop"
+
+# Verify files exist
+if (-not (Test-Path $ExePath)) {
+    Write-Host "ERROR: Executable not found at $ExePath" -ForegroundColor Red
+    exit 1
+}
+
+if (-not (Test-Path $ChecksumPath)) {
+    Write-Host "ERROR: Checksum file not found at $ChecksumPath" -ForegroundColor Red
+    exit 1
+}
+
+Write-Host "Uploading WebDropBridge $Version to Forgejo Packages..." -ForegroundColor Cyan
+
+# Get file info
+$exeSize = (Get-Item $ExePath).Length / 1MB
+$checksum = Get-Content $ChecksumPath -Raw
+
+Write-Host "File: WebDropBridge.exe ($([math]::Round($exeSize, 2)) MB)"
+Write-Host "Checksum: $($checksum.Substring(0, 16))..."
+
+# Upload executable
+Write-Host "`nUploading executable..." -ForegroundColor Yellow
+$exeUrl = "$ForgejoUrl/api/v1/repos/$Repo/packages/generic/webdrop-bridge/$Version/WebDropBridge.exe"
+
+$headers = @{
+    "Authorization" = "token $ForgejoToken"
+}
+
+try {
+    $response = Invoke-WebRequest -Uri $exeUrl `
+        -Method PUT `
+        -Headers $headers `
+        -InFile $ExePath `
+        -ContentType "application/octet-stream"
+    
+    Write-Host "✓ Executable uploaded successfully" -ForegroundColor Green
+}
+catch {
+    Write-Host "ERROR uploading executable: $_" -ForegroundColor Red
+    exit 1
+}
+
+# Upload checksum
+Write-Host "Uploading checksum..." -ForegroundColor Yellow
+$checksumUrl = "$ForgejoUrl/api/v1/repos/$Repo/packages/generic/webdrop-bridge/$Version/WebDropBridge.exe.sha256"
+
+try {
+    $response = Invoke-WebRequest -Uri $checksumUrl `
+        -Method PUT `
+        -Headers $headers `
+        -Body $checksum `
+        -ContentType "text/plain"
+    
+    Write-Host "✓ Checksum uploaded successfully" -ForegroundColor Green
+}
+catch {
+    Write-Host "ERROR uploading checksum: $_" -ForegroundColor Red
+    exit 1
+}
+
+Write-Host "`n✓ Upload complete!" -ForegroundColor Green
+Write-Host "View at: $ForgejoUrl/$Repo/packages" -ForegroundColor Cyan