fix: use specific exception types in catch blocks

Replaced 5 bare catch blocks with specific exception types:
- PveHttpClient: catch JsonException for JSON parse fallback
- PveCmdletBase: catch Exception with filter excluding OOM/SOE for polling
- VmService/ContainerService: catch PveApiException|HttpRequestException
  for offline node handling
- GetPveVmCmdlet: catch PveApiException for VM enrichment failures

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

src/PSProxmoxVE.Core/Client/PveHttpClient.cs

@@ -383,7 +383,7 @@ namespace PSProxmoxVE.Core.Client
                 if (!string.IsNullOrWhiteSpace(message))
                     return message!;
             }
-            catch
+            catch (Newtonsoft.Json.JsonException)
             {
                 // If parsing fails, fall through to returning the raw body (truncated)
             }