fix(test): add -Confirm:$false to all ConfirmImpact.High cmdlet calls in tests

ConfirmImpact.High causes interactive confirmation prompts in
non-interactive CI, blocking before ProcessRecord runs. Add
-Confirm:$false to all Stop-PveVm, Reset-PveVm, Remove-*,
Restore-*, and New-PveTemplate calls in both unit and integration tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/PSProxmoxVE.Tests/Containers/ContainerLifecycle.Tests.ps1

@@ -244,7 +244,7 @@ Describe 'Stop-PveContainer' {
     Context 'Without active session' {
         It 'Should throw when no session is active' {
             Skip-IfMissing 'Stop-PveContainer'
-            { Stop-PveContainer -Node 'pve-node1' -VmId 200 -ErrorAction Stop } |
+            { Stop-PveContainer -Node 'pve-node1' -VmId 200 -Confirm:$false -ErrorAction Stop } |
                 Should -Throw '*No active Proxmox VE session*'
         }
     }