fix(tests): resolve all 400 unit test failures to reach green

Cmdlet fixes:
- GetPveSnapshotCmdlet: add -Name filter; fix s.SnapName → s.Name
- GetPveStorageCmdlet: add -Storage name filter
- GetPveNetworkCmdlet: add -Iface optional filter
- NewPveNetworkCmdlet: rename Interface → Iface (consistency with Set/Remove)
- SetPveNetworkCmdlet, RemovePveNetworkCmdlet: rename Interface → Iface
- RemovePveNetworkCmdlet, RemovePveSdnZoneCmdlet, RemovePveSdnVnetCmdlet,
  RemovePveUserCmdlet: add ConfirmImpact = ConfirmImpact.High
- SetPveCloudInitConfigCmdlet: rename User → CiUser; move GetSession() first;
  remove duplicate session variable
- SendPveIsoCmdlet: add sha512 to ChecksumAlgorithm ValidateSet
- GetPveUserCmdlet: add -Enabled switch; refactor into MatchesFilters(); fix
  int? comparison (Enabled != 1)
- GetPvePermissionCmdlet: rename UgId → UserId
- SetPvePermissionCmdlet: rename RoleId → Role
- NewPveTemplateCmdlet: add ConfirmImpact.High; move GetSession() before
  ShouldProcess so -WhatIf-less calls throw session error first
- NewPveVmFromTemplateCmdlet: rename Node → TemplateNode with [Alias("Node")]
- RemovePveSnapshotCmdlet, RestorePveSnapshotCmdlet: move GetSession() before
  ShouldProcess so session check precedes confirm prompt

Test fixes:
- All 18 Pester test files: update DLL candidates to net9.0
- Fix foreach+It closure capture using -TestCases pattern
- Remove-PveVm, Remove-PveContainer no-session tests: add -Confirm:$false to
  bypass ConfirmImpact.High prompt before GetSession() check
- Get-PveStorageContent test: add mandatory -Node/-Storage params
- Send-PveIso test: create temp file to satisfy FileExistsValidation
- New-PveVmFromTemplate test: add NewVmId to parameter splat

Tooling:
- Invoke-Tests.ps1: add -FromTerraform, explicit lab params, fix TFM
  auto-detection via Select-Xml, fix Pester import, fix variable scoping

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PSProxmoxVE.Core/PSProxmoxVE.Core.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net10.0;net48</TargetFrameworks>
+    <TargetFrameworks>net9.0;net48</TargetFrameworks>
     <LangVersion>10.0</LangVersion>
     <Nullable>enable</Nullable>
     <RootNamespace>PSProxmoxVE.Core</RootNamespace>
@@ -22,7 +22,7 @@
     <Reference Include="System.Net.Http" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net10.0'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net9.0'">
     <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
   </ItemGroup>