Add ZVMA pre/post script recipe + env-dump examples

Adds a Kubernetes-ZVMA companion to the existing Windows-ZVM recipe:

- scripts/examples/zerto-zvma-send.ps1 - Zerto-side sender for both
  pre and post phases, packages the Zerto* env vars into a structured
  JSON body and POSTs to a {phase}-templated webhook URL.
- scripts/examples/zerto-receiver-notify.ps1 - server-side receiver
  that posts a Slack/Teams notification, with phase-aware formatting
  and ZertoForce highlighted on pre.
- scripts/examples/zerto-receiver-vm-healthcheck.ps1 - server-side
  receiver that pings + port-probes each VM in VmDisplayNames after
  failover and writes a per-run JSON report.
- scripts/examples/send-env-vars.ps1 + save-env-vars.ps1 - generic
  env-dump client/receiver pair (the diagnostic that surfaced what
  the ZVMA scripts-service container exposes).
- docs/recipes/zerto-zvma-pre-post.md - full walkthrough mirroring
  the existing Windows-ZVM recipe's structure.
- README.md and docs/README.md - link the new recipe and examples.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/examples/save-env-vars.ps1

@@ -0,0 +1,46 @@
+<#
+.SYNOPSIS
+    Server-side receiver for the env-dump webhook. Reads the JSON body from
+    stdin and writes it to a timestamped file on disk.
+
+.DESCRIPTION
+    Configure a webhook endpoint like this:
+        Executable:        powershell.exe   (or pwsh.exe)
+        Arguments:         -NoProfile -ExecutionPolicy Bypass -File C:\path\to\save-env-vars.ps1
+        Data passing:      [x] Stdin JSON
+        Run As:            Service (or any account that can write to $OutDir)
+
+    Output goes to C:\ProgramData\WebhookServer\env-dumps\<host>-<utcstamp>.json
+    by default; override with -OutDir.
+#>
+
+[CmdletBinding()]
+param(
+    [string] $OutDir = 'C:\ProgramData\WebhookServer\env-dumps'
+)
+
+$ErrorActionPreference = 'Stop'
+
+if (-not (Test-Path $OutDir)) {
+    New-Item -ItemType Directory -Path $OutDir -Force | Out-Null
+}
+
+$body = [Console]::In.ReadToEnd()
+if ([string]::IsNullOrWhiteSpace($body)) {
+    Write-Error 'Empty request body on stdin.'
+    exit 2
+}
+
+# Parse so we can pull the host name for the filename, and to fail fast on
+# malformed JSON before writing it.
+$parsed = $body | ConvertFrom-Json
+$hostName = if ($parsed.host) { $parsed.host } else { 'unknown' }
+$safeHost = ($hostName -replace '[^A-Za-z0-9_.-]', '_')
+$stamp    = (Get-Date).ToUniversalTime().ToString('yyyyMMddTHHmmssZ')
+$path     = Join-Path $OutDir "$safeHost-$stamp.json"
+
+# Persist the original body verbatim - keeps key ordering and avoids any
+# round-trip surprises from ConvertTo-Json.
+Set-Content -Path $path -Value $body -Encoding utf8
+
+Write-Host "Saved $($body.Length) bytes to $path"