fix(installer): install the Visual C++ runtime before MySQL, and log the MSI

Second failure from the Server 2019 test. The previous fix worked - msiexec went
from exit 1639 (ERROR_INVALID_COMMAND_LINE, which is why it printed its usage
dialog) to exit 1603 (ERROR_INSTALL_FAILURE), so the command line parses now and
the MSI itself is failing.

It failed in 1.1 seconds. An MSI that dies that fast has not begun installing;
it has failed a launch condition. MySQL 8.4 requires the Visual C++
redistributable and a bare Windows Server does not ship it - the same runtime
mysql.exe and mysqldump.exe import, which was visible when their DLL
dependencies were trimmed and went unnoticed.

Stage 0 now installs VC_redist.x64.exe from the bundle before touching MySQL,
skipping it when vcruntime140.dll is already present, and fails with a sentence
naming the requirement if the redistributable is absent from the bundle
altogether. vcredist\ is an optional locked payload.

msiexec also gets /l*v now. A bare 1603 names neither the failing action nor the
reason, and it is the most common MySQL install failure - diagnosing this one
took a launch-condition inference rather than a log. The MSI log lands beside
the installer's own in ProgramData, so the next failure is readable instead of
guessed at.

deploy/windows/installer/shopdb-install.ps1

@@ -677,9 +677,42 @@ Skip stage 0 and point the installer at the existing server with -DbHost.
                 Write-Log "could not start msiserver: $($_.Exception.Message)" 'WARN'
             }
         }
+        # The Visual C++ runtime, BEFORE MySQL. MySQL's MSI carries a launch
+        # condition requiring it, and a bare Windows Server does not ship it -
+        # so on a fresh box the MSI aborts in about a second with the generic
+        # exit 1603 and no indication of what was missing. That is what a real
+        # Server 2019 install did.
+        $vcMarker = Join-Path $env:windir 'system32\vcruntime140.dll'
+        if (Test-Path $vcMarker) {
+            Write-Log 'Visual C++ runtime already present' 'OK'
+        } else {
+            $vc = Get-ChildItem (Join-Path $BundleRoot 'vcredist') -Filter '*.exe' -ErrorAction SilentlyContinue |
+                  Select-Object -First 1
+            if (-not $vc) {
+                Fail 'the Visual C++ runtime is missing and no redistributable is in the bundle' @'
+MySQL will not install without it - its MSI fails with a bare exit 1603.
+Add vcredist\VC_redist.x64.exe to the bundle and rebuild, or install the
+Microsoft Visual C++ 2015-2022 Redistributable (x64) on this server by hand.
+'@
+            }
+            Write-Log "installing $($vc.Name) (MySQL requires it)"
+            if (-not $WhatIfOnly) {
+                Invoke-Native $vc.FullName @('/install','/quiet','/norestart') `
+                    'Visual C++ runtime' -TimeoutSec 600
+                Write-Log 'Visual C++ runtime installed' 'OK'
+            }
+        }
+
         # Quiet MSI. INSTALLDIR must have no trailing backslash or the MSI mis-parses it.
         Write-Log "installing $($msi.Name) (125MB, takes a minute)"
+        # /l*v: without the MSI's own log, exit 1603 says only "something went
+        # wrong" - it names neither the action nor the reason, and it is the most
+        # common MySQL failure code. Costs nothing and turns the next failure
+        # into something readable.
+        $msiLog = Join-Path $script:LogDir ('mysql-msi-{0}.log' -f (Get-Date -Format 'yyyyMMdd-HHmmss'))
+        Write-Log "MSI log: $msiLog"
         Invoke-Native 'msiexec.exe' @('/i', $msi.FullName, '/quiet', '/norestart',
+                                      '/l*v', $msiLog,
                                       "INSTALLDIR=$MysqlRoot") 'MySQL MSI' -TimeoutSec 900
     }
     # An installer exit code of 0 does NOT mean it did what you asked - the Python