Drop Windows-ZVM recipe; ZVMA is now the canonical Zerto example

The Windows ZVM is largely deprecated in favor of the ZVMA on
Kubernetes, so the older recipe and its companion sender script are
gone. The ZVMA recipe is promoted to canonical and its header no
longer references the deleted recipe.

- delete docs/recipes/zerto-pre-post-scripts.md (Windows-ZVM-only)
- delete scripts/examples/zerto-post-failover.ps1 (curl.exe sender)
- promote ZVMA recipe in README, docs/README, installation, sync-wiki

If anyone still needs the DNS-update / service-check handler from
the deleted recipe it's available in git history (commit before this
one). Happy to re-resurrect into a generic post-failover recipe if
folks ask.

scripts/examples/zerto-post-failover.ps1

@@ -1,78 +0,0 @@
-<#
-.SYNOPSIS
-    Zerto post-failover script. Fires the on-prem Webhook Server which does
-    the real work (DNS updates, service health checks, notifications).
-
-.DESCRIPTION
-    Designed to be dropped into a Zerto VPG's post-recovery script slot. The
-    Zerto Virtual Manager's PowerShell runner has a limited module set and
-    runs scripts synchronously, so this script:
-
-      - uses curl.exe (ships with Windows 10 1803+ / Server 2019+) instead
-        of any module-dependent HTTP client;
-      - calls an ASYNC webhook endpoint - the server returns 202 in
-        milliseconds and runs the actual work in the background;
-      - returns within seconds regardless of how long the post-failover
-        actions take, so Zerto's failover sequence is never blocked.
-
-    Wire this into your VPG via the Zerto UI:
-        VPG settings -> Recovery -> Scripts -> Post-Recovery Script
-        Path: C:\path\to\zerto-post-failover.ps1
-        Parameters: leave empty (we read from $env:ZertoVPGName)
-
-.NOTES
-    Configure $WebhookUrl and either:
-      - paste the bearer token directly into $Bearer (simplest, but the
-        token then lives in this file), or
-      - point $BearerFile at a file readable only by the ZVM service
-        account (better - same threat model as Zerto's own credential
-        storage).
-#>
-
-$ErrorActionPreference = 'Stop'
-
-# ----------------------------- CONFIGURE ---------------------------------
-$WebhookUrl = 'http://webhook.contoso.local:8080/hook/post-failover'
-$Bearer     = ''                              # paste here, or use $BearerFile
-$BearerFile = 'C:\ProgramData\Zerto\webhook-token.txt'   # one line: the token
-# -------------------------------------------------------------------------
-
-if (-not $Bearer -and (Test-Path $BearerFile)) {
-    $Bearer = (Get-Content -LiteralPath $BearerFile -TotalCount 1).Trim()
-}
-if (-not $Bearer) {
-    throw "No bearer token. Set `$Bearer in this script or write the token to $BearerFile."
-}
-
-# Compose the payload. Zerto exposes a few env vars; fall back gracefully.
-$payload = @{
-    operation = 'failover'
-    vpg       = if ($env:ZertoVPGName) { $env:ZertoVPGName } else { 'unknown' }
-    timestamp = (Get-Date).ToUniversalTime().ToString('o')
-} | ConvertTo-Json -Compress
-
-# curl on Windows handles long / quoted JSON better via @file than via -d "...".
-$tempBody = Join-Path $env:TEMP ("zerto-webhook-{0}.json" -f ([guid]::NewGuid()))
-$payload | Out-File -FilePath $tempBody -Encoding utf8 -NoNewline
-
-try {
-    Write-Host "POST $WebhookUrl  (vpg=$($env:ZertoVPGName))"
-    & curl.exe `
-        --silent --show-error --fail-with-body `
-        --max-time 10 `
-        -X POST `
-        -H "Authorization: Bearer $Bearer" `
-        -H "Content-Type: application/json" `
-        -d "@$tempBody" `
-        "$WebhookUrl"
-    if ($LASTEXITCODE -ne 0) {
-        # curl prints its own error to stderr; surface a non-zero exit so Zerto's
-        # script log records the failure but we don't block the failover.
-        Write-Warning "Webhook call failed with curl exit $LASTEXITCODE; continuing."
-    } else {
-        Write-Host "Webhook accepted (run id is in the response above)."
-    }
-}
-finally {
-    Remove-Item $tempBody -ErrorAction SilentlyContinue
-}

scripts/sync-wiki.ps1

@@ -65,7 +65,7 @@ $mapping.Add('runas-modes.md',                    'Run-As-Modes')
 $mapping.Add('service-account-and-ad.md',         'Service-Account-and-AD')
 $mapping.Add('network-and-security.md',           'Network-and-Security')
 $mapping.Add('troubleshooting.md',                'Troubleshooting')
-$mapping.Add('recipes/zerto-pre-post-scripts.md', 'Recipe-Zerto-Failover')
+$mapping.Add('recipes/zerto-zvma-pre-post.md',    'Recipe-Zerto-ZVMA')
 $mapping.Add('recipes/github-style-hmac.md',      'Recipe-GitHub-HMAC')
 $mapping.Add('recipes/ui-on-desktop.md',          'Recipe-UI-on-Desktop')
 
@@ -94,7 +94,7 @@ function New-Sidebar() {
     }
     $lines += ""
     $lines += "## Recipes"
-    foreach ($key in @('recipes/zerto-pre-post-scripts.md','recipes/github-style-hmac.md','recipes/ui-on-desktop.md')) {
+    foreach ($key in @('recipes/zerto-zvma-pre-post.md','recipes/github-style-hmac.md','recipes/ui-on-desktop.md')) {
         $slug = $mapping[$key]
         $lines += "- [$($slug -replace '^Recipe-' -replace '-', ' ')]($slug)"
     }