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- e2e-test-plan.md: removed the outdated 'Word COM fails under SYSTEM / requires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

docs/formation-system.md

@@ -238,7 +238,7 @@ Flags for support conversations (escalation, priority, category).
   - Converts via Word COM, drops PDF in `converted/` bucket
   - Heartbeat file at `minio://performancewest/docserver-heartbeat.json` (60s interval)
   - Atomic uploads via `.tmp_` prefix + `copy_object` rename
-  - Task Scheduler: `PW-DocserverWorker` — auto-restart on failure
+  - Task Scheduler: `PW-DocserverWorker` — self-healing: restarts on failure (99×/1 min) + AtStartup and a 5-min repeating trigger (relaunches within ~5 min if the process dies). The worker also retries MinIO on outage instead of exiting.
 - **Fallback:** LibreOffice headless (`soffice --headless --convert-to pdf`) auto-activates when DocServer heartbeat stale (>5 min)
 - **E2E tested:** 36KB DOCX → 82KB PDF in 12 seconds total round-trip