chore(java): consolidate mss-failsafe to single canonical copy

Replace the stale multi-module java/mss-failsafe skeleton (old user-management
prototype) with the active single-module machine-safety inspection app that was
living in its own standalone repo at the repo root.

- Remove old java/mss-failsafe/ multi-module tree (mss, userdata, userManagement,
  mssfailsafe.datalayer, mssfailsafeWeblayer) incl. committed build artifacts
- Add the active app (PrimeFaces 11 / JSF 2.3 / Hibernate 5.6 / iText / POI)
  flattened into java/mss-failsafe/ as the only mss-failsafe in git
- Working tree captured = master tip 2a142b5 + in-progress uncommitted work
  (incl. .github/*.instructions.md AI-context files)
- Archive the standalone repo's 33-commit history in GIT_HISTORY_ARCHIVE.md
  since its .git was not migrated

This is the source of truth / base for the upcoming upgraded rewrite.

java/mss-failsafe/.github/questionnaire_workflow.instructions.md

@@ -0,0 +1,28 @@
+# Questionnaire Workflow Instructions
+
+## Add
+areaManager.addQuestionnaireToSecurityArea(area, questionnaire)
+- area ggf. re-laden
+- Wrapper erzeugen
+- Persist wrapper + merge area
+- Rückgabe: aktualisierte Area
+
+## Remove
+areaManager.removeQuestionnaireFromSecurityArea(area, wrapper)
+- area & wrapper re-laden
+- Collection remove, em.remove(wrapper), em.merge(area)
+
+## Available List
+getAvailableQuestionnaires(area): SELECT q FROM Questionaire q ORDER BY q.name
+- Filter: bereits zugeordnete Namen
+
+## Edge Cases
+- Null area/questionnaire -> Fehlermeldung
+- Race condition -> nach Add/Remove refreshSelected()
+
+## Verbesserungen
+- ID statt Name für Filter
+- Duplikatprüfung direkt im Manager
+
+---
+Aktualisiert: 2025-10-20