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/general_project.instructions.md

@@ -0,0 +1,31 @@
+# General Project Instructions
+
+## Quick Facts
+- Java EE 8 (javax) / Java 11 / WAR
+- JSF + PrimeFaces + PrimeFlex
+- Persistence Unit: pu_person
+- Logging: Log4j2
+
+## Build
+mvn clean package -> target/mss-1.0-SNAPSHOT.war
+
+## Core Patterns
+- Manager: CRUD + Fachmethoden (extends AbstractManager)
+- Controller: UI State + Messages + PDF (extends AbstractController)
+- Negative IDs für temporäre Objekte
+
+## PDF
+- iText7 bevorzugen; Legacy iText5 entfernen später
+
+## Improvements Roadmap
+- Vereinheitlichte Exception Strategie
+- Test Suite aufbauen
+- Migration nach Jakarta EE (Namespace Wechsel)
+
+## AI Generation Hints
+- Halte Signaturen stabil
+- Keine neuen Frameworks
+- Initialisiere Lazy Collections vor Nutzung
+
+---
+Aktualisiert: 2025-10-20