OX-02 P14: diagnose why Owen.VisualStudio.dll is not in devenv

The run on bd0ef66 realized Use.cs, read the Error List through UI Automation
(CS0029 | LiveFixture | Use.cs | 10), but Owen.VisualStudio.dll never loaded into
devenv and the ActivityLog does not mention it. Collect the hive's installed
extensions, the MEF composition's .err files and the VSIXInstaller logs, and stop
early when the extension is not in the process.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011ZFvhLx1fM9Gerg4dKsZcL

Author: claude

scripts/vs/owen-vs-acceptance.ps1

@@ -71,6 +71,23 @@ function Retry([scriptblock]$Block, [int]$Seconds = 60) {
     }
 }
 
+# Where an installed extension and the MEF composition's own errors live, for the evidence.
+function Collect-Diagnostics {
+    $hive = Get-ChildItem (Join-Path $env:LOCALAPPDATA 'Microsoft\VisualStudio') -Directory -ErrorAction SilentlyContinue |
+        Where-Object { $_.Name -like "*$RootSuffix" }
+    foreach ($h in $hive) {
+        Log "hive: $($h.FullName)"
+        Get-ChildItem (Join-Path $h.FullName 'Extensions') -Recurse -ErrorAction SilentlyContinue |
+            Where-Object { $_.Name -like '*Owen*' -or $_.Name -like '*.vsixmanifest' -or $_.Name -like 'extensions.*' } |
+            ForEach-Object { Log "  ext: $($_.FullName)" }
+        Get-ChildItem (Join-Path $h.FullName 'ComponentModelCache') -ErrorAction SilentlyContinue | ForEach-Object {
+            Log "  cache: $($_.Name) $($_.Length)"
+            if ($_.Name -like '*.err') { Copy-Item $_.FullName (Join-Path $Out $_.Name) -ErrorAction SilentlyContinue }
+        }
+    }
+    Get-ChildItem $env:TEMP -Filter 'dd_VSIXInstaller*' -ErrorAction SilentlyContinue | ForEach-Object { Copy-Item $_.FullName $Out -ErrorAction SilentlyContinue }
+}
+
 # ---- Visual Studio ----------------------------------------------------------------------------
 $vswhere = "${env:ProgramFiles(x86)}\Microsoft Visual Studio\Installer\vswhere.exe"
 $vs = (& $vswhere -latest -products * -format json | ConvertFrom-Json)[0]
@@ -151,8 +168,16 @@ for ($k = 0; $k -lt 60 -and -not $loaded; $k++) {
     try { $loaded = @((Get-Process -Id $proc.Id).Modules | Where-Object { $_.FileName -like '*Owen.VisualStudio.dll' })[0] } catch { }
     if (-not $loaded) { Start-Sleep -Seconds 1 }
 }
+if (-not $loaded) { Collect-Diagnostics }
 Check "vsix-loaded" ($null -ne $loaded) "Owen.VisualStudio.dll in devenv: $(if ($loaded) { $loaded.FileName } else { 'not loaded' })"
 Shot "opened"
+if (-not $loaded) {
+    # nothing below can pass without the extension in the process: stop with the evidence
+    $results.failed = $true
+    $results | ConvertTo-Json -Depth 8 | Set-Content (Join-Path $Out 'results.json') -Encoding UTF8
+    Stop-Process -Id $proc.Id -Force -ErrorAction SilentlyContinue
+    exit 1
+}
 $td = Retry { $doc.Object('TextDocument') }
 
 # ---- trace ------------------------------------------------------------------------------------