docserver: self-healing Task Scheduler config + docs

Companion to the worker MinIO-retry fix. Makes the worker auto-recover from
process death (crash, manual kill, missed boot trigger), not just MinIO outages.

- start_worker.bat: propagate Python's exit code (exit /b %rc%) so Task
  Scheduler can actually detect a failed run (it previously always exited 0).
- reconfigure_task.ps1 (new): re-registers PW-DocserverWorker with
  RestartCount=99 / 1-min interval, StartWhenAvailable, and two triggers —
  AtStartup plus a 5-min repeating trigger with MultipleInstances=IgnoreNew, so
  a dead worker relaunches within ~5 min and never double-runs. Idempotent.
- install.ps1: same self-healing settings for fresh installs.
- Verified on the box: killed the worker -> task relaunched it; firing again
  while running stayed at one instance.

Docs updated to match reality:
- docserver/README.md: new 'Reliability / self-healing' section.
- document-generation.md: corrected the stale 'Flask DocServer :5050 / HTTP'
  description to the actual MinIO outbound-only transport.
- e2e-test-plan.md: removed the outdated 'Word COM fails under SYSTEM / requires
  RDP after every reboot' limitation; now self-healing under SYSTEM session 0.
- infrastructure.md: fixed VM spec (Win Server 2019, Word 16.0, Python 3.13,
  SSH port 22422) + self-healing note.
- architecture.md / formation-system.md: trigger + self-healing details.

docserver/reconfigure_task.ps1

@@ -0,0 +1,46 @@
+# Reconfigures the PW-DocserverWorker scheduled task for self-healing:
+#   - restart up to 99x at 1-min intervals if the task action fails
+#   - StartWhenAvailable (catch up if a trigger was missed)
+#   - a repeating safety trigger every 5 min with MultipleInstances=IgnoreNew,
+#     so if the worker process ever dies (crash, manual kill, missed boot
+#     trigger) it relaunches within ~5 min instead of waiting for a reboot
+#   - keeps AtStartup + SYSTEM/Highest (current working config)
+# Idempotent: safe to re-run. Run as Administrator.
+$ErrorActionPreference = 'Stop'
+$taskName = 'PW-DocserverWorker'
+$appDir   = 'C:\docserver'
+
+$action = New-ScheduledTaskAction -Execute 'cmd.exe' `
+    -Argument "/c `"$appDir\start_worker.bat`"" -WorkingDirectory $appDir
+
+# Two triggers: at boot, and a repeating safety net every 5 minutes (indefinitely).
+$atStartup = New-ScheduledTaskTrigger -AtStartup
+$repeat    = New-ScheduledTaskTrigger -Once -At (Get-Date) `
+    -RepetitionInterval (New-TimeSpan -Minutes 5)
+# Some Windows builds cap repetition without an explicit long duration; set ~10y.
+try { $repeat.Repetition.Duration = 'P3650D' } catch {}
+
+$settings = New-ScheduledTaskSettingsSet `
+    -ExecutionTimeLimit (New-TimeSpan -Hours 0) `
+    -RestartCount 99 `
+    -RestartInterval (New-TimeSpan -Minutes 1) `
+    -StartWhenAvailable `
+    -MultipleInstances IgnoreNew `
+    -AllowStartIfOnBatteries `
+    -DontStopIfGoingOnBatteries
+
+$principal = New-ScheduledTaskPrincipal -UserId 'SYSTEM' `
+    -LogonType ServiceAccount -RunLevel Highest
+
+Register-ScheduledTask -TaskName $taskName -Action $action `
+    -Trigger @($atStartup, $repeat) -Settings $settings -Principal $principal `
+    -Description 'Performance West DOCX-to-PDF worker (MinIO + Word COM). Self-healing: restarts on failure + 5-min safety trigger.' `
+    -Force | Out-Null
+
+Write-Host "Reconfigured ${taskName}:"
+$ti = Get-ScheduledTask -TaskName $taskName
+$ti.Triggers | ForEach-Object { Write-Host ("  trigger: " + $_.CimClass.CimClassName) }
+$s = $ti.Settings
+Write-Host ("  RestartCount=" + $s.RestartCount + " RestartInterval=" + $s.RestartInterval +
+            " StartWhenAvailable=" + $s.StartWhenAvailable + " MultipleInstances=" + $s.MultipleInstances)
+Write-Host ("  State=" + $ti.State)