fix(staging): ASCII-only echo so PowerShell doesn't choke on em dash

The deploy succeeded on the runner but the final 'Staging endpoints' step
failed: act_runner writes the step as UTF-8 while Windows PowerShell 5.1 reads
.ps1 as ANSI, so the em dash mis-decoded and PowerShell saw an unterminated
string. Replace it with a plain hyphen. Keeps all host-mode run: content ASCII.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/deploy-staging.yml

@@ -45,4 +45,4 @@ jobs:
 
       - name: Staging endpoints
         shell: powershell
-        run: Write-Host "Staging up — Frontend http://localhost:18081  API http://localhost:18080/swagger"
+        run: Write-Host "Staging up - Frontend http://localhost:18081  API http://localhost:18080/swagger"