openup: architecture notebook + EA diagram renders

- analysis-design/architecture-notebook.md: Architecture Notebook work
  product in the keyfob docx template structure (10 sections), grounded
  in mapping / design note / supplementary specs; embeds the component
  model and all 12 realization figures
- scripts/openup/export-diagram-images.ps1: read-only EA COM renderer
  (EA-15 findings: image API on ProjectInterface, OpenDiagram before
  export or blank stub, type 0 = PNG); renders reflect manual layouts
- renders: requirements/use-case-overview.png, analysis-design/
  uc-01..12-realization.png + component-architecture.png; embedded as
  figures in use-case-model.md and uc-realization-mapping.md
- BUILD-CHECKLIST 6.4 documents the exporter

scripts/openup/export-diagram-images.ps1

@@ -0,0 +1,90 @@
+# Skara Brae — EA diagram image exporter.
+# Renders the model's diagrams to PNG for embedding in the OpenUP markdown documents.
+# READ-ONLY on the model (opens diagrams, renders, closes; no model mutation).
+#
+# EA-15 findings baked in (probe session 2026-10-05):
+# - the image methods live on ProjectInterface, NOT on Repository
+#   (Repository.SaveImageToPath exists but always returns False);
+# - PutDiagramImageToFile(id, path, type) with type 0 = PNG;
+# - the diagram must be OPEN (repo.OpenDiagram) before export, else a blank
+#   241x151 stub is written;
+# - works with EA hidden (app.Visible = $false).
+#
+# Output (keyfob-station convention: requirements overview next to the UC docs,
+# realization + design figures in analysis-design/):
+#   docs/openup/requirements/use-case-overview.png
+#   docs/openup/analysis-design/uc-01-realization.png .. uc-12-realization.png
+#   docs/openup/analysis-design/component-architecture.png
+
+$ErrorActionPreference = 'Stop'
+
+$repoRoot  = (Resolve-Path (Join-Path $PSScriptRoot '..\..')).Path
+$modelPath = Join-Path $repoRoot 'docs\openup\model\skara-brae.eapx'
+if (-not (Test-Path $modelPath)) {
+    Write-Output "MISSING $modelPath"
+    exit 1
+}
+$reqDir = Join-Path $repoRoot 'docs\openup\requirements'
+$adDir  = Join-Path $repoRoot 'docs\openup\analysis-design'
+$null = New-Item -ItemType Directory -Force -Path $reqDir, $adDir
+
+$step = 'start'
+$app = $null
+$eaBefore = @(Get-Process -Name EA -ErrorAction SilentlyContinue | Select-Object -ExpandProperty Id)
+
+function Export-Diagram([object]$project, [object]$repo, [int]$diagramId, [string]$outPath) {
+    if (Test-Path $outPath) { Remove-Item $outPath -Force }
+    $null = $repo.OpenDiagram($diagramId)
+    Start-Sleep -Seconds 2
+    $null = $project.PutDiagramImageToFile($diagramId, $outPath, 0)
+    try { $null = $repo.CloseDiagram($diagramId) } catch { }
+    if (-not (Test-Path $outPath)) { throw "no image written: $outPath" }
+    $bytes = (Get-Item $outPath).Length
+    if ($bytes -lt 5000) { throw "suspiciously small render ($bytes bytes): $outPath" }
+    Write-Output "exported: $outPath ($bytes bytes)"
+}
+
+try {
+    $app = New-Object -ComObject EA.App
+    $app.Visible = $false
+    $repo = $app.Repository
+    $null = $repo.OpenFile($modelPath)
+    $root = $repo.Models.GetAt([int]0)
+    $project = $repo.GetProjectInterface()
+
+    $step = 'use case overview'
+    $ucModel = $root.Packages.GetByName('Requirements').Packages.GetByName('Use Case Model')
+    $ucModel.Diagrams.Refresh()
+    $overview = $ucModel.Diagrams.GetByName('Skara Brae Use Case Overview')
+    Export-Diagram $project $repo $overview.DiagramID (Join-Path $reqDir 'use-case-overview.png')
+
+    $step = 'realization diagrams'
+    $analysisDesign = $root.Packages.GetByName('Analysis-Design')
+    $analysisDesign.Packages.Refresh()
+    for ($p = 0; $p -lt $analysisDesign.Packages.Count; $p++) {
+        $pkg = $analysisDesign.Packages.GetAt([int]$p)
+        if ($pkg.Name -notlike 'UC-?? Realization') { continue }
+        $pkg.Diagrams.Refresh()
+        if ($pkg.Diagrams.Count -lt 1) { throw "no diagram in $($pkg.Name)" }
+        $number = $pkg.Name.Substring(3, 2)
+        Export-Diagram $project $repo $pkg.Diagrams.GetAt([int]0).DiagramID (Join-Path $adDir ("uc-{0}-realization.png" -f $number.ToLower()))
+    }
+
+    $step = 'component architecture'
+    $design = $analysisDesign.Packages.GetByName('Design')
+    $design.Diagrams.Refresh()
+    $componentDiagram = $design.Diagrams.GetByName('Component Architecture')
+    Export-Diagram $project $repo $componentDiagram.DiagramID (Join-Path $adDir 'component-architecture.png')
+
+    $null = $repo.CloseFile()
+    Write-Output 'EXPORT OK - 14 diagrams rendered'
+}
+catch {
+    Write-Output "FAILED at [$step]: $($_.Exception.Message)"
+    exit 1
+}
+finally {
+    Get-Process -Name EA -ErrorAction SilentlyContinue |
+        Where-Object { $eaBefore -notcontains $_.Id } |
+        ForEach-Object { Stop-Process -Id $_.Id -Force }
+}