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/refresh_fake_id.instructions.md

@@ -0,0 +1,25 @@
+# Refresh & Fake ID Instructions
+
+## Fake ID
+- Negative Long Werte (<0) = temporär
+- Sequenz: -1, -2, -3 ... (kleinste negative - 1)
+- Erzeugung: AbstractController.createFakeID(Collection<E>)
+
+## Persist
+- Vor Speichern: if id < 0 -> setId(null)
+- save/saveAll: id == null => persist, sonst merge
+
+## Refresh
+- AbstractController.refrehSelected() (Tippfehler) -> getManager().refresh(selected)
+- AbstractManager.refresh(entity): if id == null -> save(entity); merge + Hibernate.initialize(entity)
+
+## Best Practices
+- Nach Add/Remove Child Collections refresh
+- Beim Klonen zuerst Quelle laden
+
+## Verbesserungen
+- Methode umbenennen zu refreshSelected()
+- JavaDoc für createFakeID
+
+---
+Aktualisiert: 2025-10-20