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- e2e-test-plan.md: removed the outdated 'Word COM fails under SYSTEM / requires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/start_worker.bat

@@ -0,0 +1,17 @@
+@echo off
+setlocal enabledelayedexpansion
+cd /d C:\docserver
+
+echo [%date% %time%] Starting Performance West Docserver Worker...
+
+for /f "usebackq tokens=1,* delims==" %%a in ("C:\docserver\docserver.env") do (
+    set "ln=%%a"
+    if not "!ln:~0,1!"=="#" (
+        if not "%%a"=="" set "%%a=%%b"
+    )
+)
+
+C:\Python313\python.exe C:\docserver\docserver_worker.py
+set "rc=%errorlevel%"
+echo [%date% %time%] Worker exited with code %rc%.
+endlocal & exit /b %rc%