fix(ci): improve release build diagnostics and encoding

- run build.py with UTF-8 env in release workflow

- capture full build output to dist/build.log and print it on failure

- extend ISCC output decoding in build.py with UTF-16 fallbacks

.gitea/workflows/release.yml

@@ -114,8 +114,20 @@ jobs:
       - name: Build release zip
         if: env.CONTINUE == 'true'
         shell: powershell
+        env:
+          PYTHONUTF8: "1"
+          PYTHONIOENCODING: "utf-8"
         run: |
-          python build.py
+          $ErrorActionPreference = "Continue"
+          $buildLog = "dist/build.log"
+          New-Item -ItemType Directory -Force -Path "dist" | Out-Null
+          python build.py *>&1 | Tee-Object -FilePath $buildLog
+          $code = $LASTEXITCODE
+          if ($code -ne 0) {
+            Write-Host "Build failed with exit code $code. Dumping build log:"
+            Get-Content -Path $buildLog -Raw
+            exit $code
+          }
 
       - name: Ensure artifacts exist
         if: env.CONTINUE == 'true'