feat(B-PLUGIN-MINIAPP-WIRE): MiniApp Registry als Singleton — gemeinsame Registry für alle Plugins

B-PLUGIN-MINIAPP-WIRE: MiniAppRegistry Singleton-Pattern
- get_miniapp_registry() / reset_miniapp_registry() in miniapp_registry.py
- Alle 6 MiniAppRegistry() Instanziierungen durch get_miniapp_registry() ersetzt
- automation/plugin.py (on_activate/on_deactivate), automation/routes.py (3x), kommunikation/plugin.py
- contracts.py: get_miniapp_registry + reset_miniapp_registry exportiert
- 0 verbleibende MiniAppRegistry() Instanziierungen außerhalb miniapp_registry.py

Tests: 12 Tests in test_miniapp_registry.py — alle grün
- Singleton, Register/List, UnregisterPlugin, Plugin-Lifecycle-Integration

app/plugins/builtins/kommunikation/contracts.py

@@ -17,6 +17,8 @@ from app.plugins.builtins.contracts import get_contract_registry
 from app.plugins.builtins.kommunikation.miniapp_registry import (
     MiniAppDef,
     MiniAppRegistry,
+    get_miniapp_registry,
+    reset_miniapp_registry,
 )
 from app.plugins.builtins.kommunikation.models import (
     CommConversation,
@@ -60,6 +62,8 @@ class KommunikationContract:
     # ─── mini-app registry ───
     MiniAppRegistry = MiniAppRegistry
     MiniAppDef = MiniAppDef
+    get_miniapp_registry = staticmethod(get_miniapp_registry)
+    reset_miniapp_registry = staticmethod(reset_miniapp_registry)
 
     # ─── models (read-only for queries) ───
     CommConversation = CommConversation
@@ -79,6 +83,8 @@ __all__ = [
     "get_participant_registry",
     "MiniAppRegistry",
     "MiniAppDef",
+    "get_miniapp_registry",
+    "reset_miniapp_registry",
     "parse_mentions",
     "get_conversation",
     "get_messages",