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/send-env-vars.ps1

@@ -0,0 +1,68 @@
+<#
+.SYNOPSIS
+    Collects env vars from PowerShell and bash, packages them into a single
+    JSON object, and POSTs the result to a Webhook Server endpoint.
+
+.DESCRIPTION
+    Output JSON shape:
+        {
+          "host":      "<computername>",
+          "capturedAt":"2026-05-08T12:34:56Z",
+          "pwsh":      { "VAR": "value", ... },
+          "bash":      { "VAR": "value", ... }
+        }
+
+    Pair this with `save-env-vars.ps1` on the server side - configure an
+    endpoint with StdinJson enabled and that script as the executable.
+#>
+
+[CmdletBinding()]
+param(
+    [string] $WebhookUrl = 'http://localhost:8080/hook/env-dump',
+    [string] $Bearer     = '',
+    [string] $BashExe    = 'bash'
+)
+
+$ErrorActionPreference = 'Stop'
+
+# --- pwsh env vars --------------------------------------------------------
+$pwshVars = [ordered]@{}
+Get-ChildItem Env: | Sort-Object Name | ForEach-Object {
+    $pwshVars[$_.Name] = $_.Value
+}
+
+# --- bash env vars --------------------------------------------------------
+$bashVars = [ordered]@{}
+$bashCmd  = Get-Command $BashExe -ErrorAction SilentlyContinue
+if ($null -ne $bashCmd) {
+    # `env -0` separates entries with NUL so values containing newlines stay intact.
+    $raw = & $bashCmd.Source -c 'env -0' 2>$null
+    if ($LASTEXITCODE -eq 0 -and $raw) {
+        foreach ($entry in ($raw -split "`0")) {
+            if ([string]::IsNullOrEmpty($entry)) { continue }
+            $eq = $entry.IndexOf('=')
+            if ($eq -lt 1) { continue }
+            $bashVars[$entry.Substring(0, $eq)] = $entry.Substring($eq + 1)
+        }
+    }
+} else {
+    Write-Warning "bash not found on PATH (looked for '$BashExe'); 'bash' section will be empty."
+}
+
+# --- assemble payload -----------------------------------------------------
+$payload = [ordered]@{
+    host       = $env:COMPUTERNAME
+    capturedAt = (Get-Date).ToUniversalTime().ToString('o')
+    pwsh       = $pwshVars
+    bash       = $bashVars
+}
+
+$json = $payload | ConvertTo-Json -Depth 5 -Compress
+
+# --- POST -----------------------------------------------------------------
+$headers = @{ 'Content-Type' = 'application/json' }
+if ($Bearer) { $headers['Authorization'] = "Bearer $Bearer" }
+
+Write-Host "POST $WebhookUrl  ($($json.Length) bytes; pwsh=$($pwshVars.Count), bash=$($bashVars.Count))"
+$response = Invoke-RestMethod -Method Post -Uri $WebhookUrl -Headers $headers -Body $json
+$response | ConvertTo-Json -Depth 5