fix(release): retry uploads with backoff + drop Gitea workflows

Gitea/nginx intermittently returns 504 on large multipart uploads even
when curl successfully streamed the body. Add up to 4 retries with
exponential backoff (15s/45s/2m/5m). Before each retry, check whether
the asset is actually present server-side at the expected size — Gitea
sometimes accepts the body but times out the response, so the file is
already there.

Also drop .gitea/workflows/* — we use release.ps1 locally and Gitea
Actions runners are not configured, so every push was leaving queued/
failed workflow runs in the Actions tab.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/upload-release-assets.ps1

@@ -157,21 +157,66 @@ if ($curlCmd) {
   }
 }
 
+$maxRetries = 4
+$backoffs   = @(15, 45, 120, 300)  # seconds between attempts
+
 foreach ($asset in @($installer, $blockmap, $manifest)) {
   $name = Split-Path $asset -Leaf
   $size = (Get-Item $asset).Length
-  Write-Host ("Uploading {0} ({1:N1} MB)..." -f $name, ($size / 1MB)) -ForegroundColor Cyan
   $uri = "$apiBase/repos/$repoOwner/$repoName/releases/$($release.id)/assets?name=$([uri]::EscapeDataString($name))"
-  # -f: fail on HTTP errors; -s -S: silent but show errors; --data-binary @file
-  & $curl `
-    --fail-with-body `
-    --silent --show-error `
-    -H "Authorization: token $env:GITEA_TOKEN" `
-    -H "Content-Type: application/octet-stream" `
-    --data-binary "@$asset" `
-    $uri
-  if ($LASTEXITCODE -ne 0) {
-    Write-Error "Upload failed for $name (curl exit $LASTEXITCODE)"
+
+  $attempt = 0
+  $uploaded = $false
+  while (-not $uploaded -and $attempt -le $maxRetries) {
+    if ($attempt -gt 0) {
+      $wait = $backoffs[[Math]::Min($attempt - 1, $backoffs.Length - 1)]
+      Write-Host ("  Retrying in {0}s (attempt {1}/{2})..." -f $wait, ($attempt + 1), ($maxRetries + 1)) -ForegroundColor Yellow
+      Start-Sleep -Seconds $wait
+
+      # Re-check whether prior attempt actually succeeded server-side before
+      # 504-ing the client. If asset is already there, treat as success.
+      try {
+        $check = Invoke-RestMethod `
+          -Uri "$apiBase/repos/$repoOwner/$repoName/releases/$($release.id)/assets" `
+          -Method Get -Headers $headers
+        $existing = $check | Where-Object { $_.name -eq $name }
+        if ($existing -and $existing.size -eq $size) {
+          Write-Host "  Asset already present server-side ($($existing.size) bytes) — skipping retry." -ForegroundColor DarkGray
+          $uploaded = $true
+          break
+        }
+        # If asset is present but with wrong size (half-uploaded), delete first.
+        if ($existing) {
+          Write-Host "  Removing partial asset id=$($existing.id) ($($existing.size) bytes) before retry..." -ForegroundColor DarkGray
+          Invoke-RestMethod `
+            -Uri "$apiBase/repos/$repoOwner/$repoName/releases/$($release.id)/assets/$($existing.id)" `
+            -Method Delete -Headers $headers | Out-Null
+        }
+      } catch {
+        # If the list call itself fails, just proceed with the retry.
+      }
+    }
+
+    Write-Host ("Uploading {0} ({1:N1} MB)..." -f $name, ($size / 1MB)) -ForegroundColor Cyan
+    & $curl `
+      --fail-with-body `
+      --silent --show-error `
+      --connect-timeout 30 `
+      --max-time 900 `
+      -H "Authorization: token $env:GITEA_TOKEN" `
+      -H "Content-Type: application/octet-stream" `
+      --data-binary "@$asset" `
+      $uri
+    if ($LASTEXITCODE -eq 0) {
+      $uploaded = $true
+    } else {
+      Write-Host "  curl exit $LASTEXITCODE — will retry." -ForegroundColor Yellow
+      $attempt++
+    }
+  }
+
+  if (-not $uploaded) {
+    Write-Error "Upload failed for $name after $($maxRetries + 1) attempts."
     exit 1
   }
 }