Windows FMA - Mattermost (#46479)

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-->

## Summary by CodeRabbit

* **New Features**
* Added Windows platform support for Mattermost v6.0.4, including MSI
installer with automated deployment and uninstall capabilities,
integrity verification, and upgrade management.

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ee/maintained-apps/inputs/winget/mattermost.json

@@ -0,0 +1,10 @@
+{
+  "name": "Mattermost",
+  "slug": "mattermost/windows",
+  "package_identifier": "Mattermost.MattermostDesktop",
+  "unique_identifier": "Mattermost",
+  "installer_arch": "x64",
+  "installer_type": "msi",
+  "installer_scope": "machine",
+  "default_categories": ["Communication"]
+}

ee/maintained-apps/outputs/apps.json

@@ -1408,6 +1408,13 @@
       "unique_identifier": "Mattermost.Desktop",
       "description": "Mattermost is an open-source, self-hosted Slack-alternative."
     },
+    {
+      "name": "Mattermost",
+      "slug": "mattermost/windows",
+      "platform": "windows",
+      "unique_identifier": "Mattermost",
+      "description": "Mattermost is an open-source, self-hosted Slack-alternative."
+    },
     {
       "name": "Messenger",
       "slug": "messenger/darwin",

ee/maintained-apps/outputs/mattermost/windows.json

@@ -0,0 +1,23 @@
+{
+  "versions": [
+    {
+      "version": "6.0.4",
+      "queries": {
+        "exists": "SELECT 1 FROM programs WHERE name = 'Mattermost' AND publisher = 'Mattermost, Inc.';",
+        "patched": "SELECT 1 WHERE NOT EXISTS (SELECT 1 FROM programs WHERE name = 'Mattermost' AND publisher = 'Mattermost, Inc.' AND version_compare(version, '6.0.4') < 0);"
+      },
+      "installer_url": "https://releases.mattermost.com/desktop/6.0.4/mattermost-desktop-6.0.4-win-x64.msi",
+      "install_script_ref": "8959087b",
+      "uninstall_script_ref": "3e27a190",
+      "sha256": "7855edeeb712420422d0b208f4b16cbd35e6eff79823f717d4e8e0afd0ca0e14",
+      "default_categories": [
+        "Communication"
+      ],
+      "upgrade_code": "{8523DAF0-699D-4CC7-9A65-C5E696A9DE6D}"
+    }
+  ],
+  "refs": {
+    "3e27a190": "# Fleet uninstalls app by finding all related product codes for the specified upgrade code\n$inst = New-Object -ComObject \"WindowsInstaller.Installer\"\n$timeoutSeconds = 300  # 5 minute timeout per product\n\nforeach ($product_code in $inst.RelatedProducts('{8523DAF0-699D-4CC7-9A65-C5E696A9DE6D}')) {\n    $process = Start-Process msiexec -ArgumentList @(\"/quiet\", \"/x\", $product_code, \"/norestart\") -PassThru\n    \n    # Wait for process with timeout\n    $completed = $process.WaitForExit($timeoutSeconds * 1000)\n    \n    if (-not $completed) {\n        Stop-Process -Id $process.Id -Force -ErrorAction SilentlyContinue\n        Exit 1603  # ERROR_UNINSTALL_FAILURE\n    }\n    \n    # If the uninstall failed, bail\n    if ($process.ExitCode -ne 0) {\n        Write-Output \"Uninstall for $($product_code) exited $($process.ExitCode)\"\n        Exit $process.ExitCode\n    }\n}\n\n# All uninstalls succeeded; exit success\nExit 0\n",
+    "8959087b": "$logFile = \"${env:TEMP}/fleet-install-software.log\"\n\ntry {\n\n$installProcess = Start-Process msiexec.exe `\n  -ArgumentList \"/quiet /norestart /lv ${logFile} /i `\"${env:INSTALLER_PATH}`\"\" `\n  -PassThru -Verb RunAs -Wait\n\nGet-Content $logFile -Tail 500\n\nExit $installProcess.ExitCode\n\n} catch {\n  Write-Host \"Error: $_\"\n  Exit 1\n}\n"
+  }
+}