refactor(#356): DSAR-Fachlogik vollstaendig aus dem Core extrahiert — dsar_collect/dsar_erase in die 5 beteiligten Contracts (contacts, mail, tasks, calendar, kommunikation); core/jobs.py sammelt/loescht nur Core-eigene Daten und iteriert generisch ueber die Plugin-Registry; neue Plugins liefern DSAR-Kategorien ohne Core-Aenderung; Counts-/Category-Keys unveraendert; tasks/contracts.py von Patch-Artefakt bereinigt

fixes #356

app/plugins/builtins/kommunikation/contracts.py

@@ -13,6 +13,11 @@ instead of importing from internal modules directly.
 
 from __future__ import annotations
 
+from typing import Any
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
 from app.plugins.builtins.contracts import get_contract_registry
 from app.plugins.builtins.kommunikation.miniapp_registry import (
     MiniAppDef,
@@ -74,6 +79,31 @@ class KommunikationContract:
     CommMessage = CommMessage
     CommParticipant = CommParticipant
 
+    @staticmethod
+    async def dsar_collect(
+        db: AsyncSession, tenant_id: Any, user_id: Any
+    ) -> dict[str, Any]:
+        """GDPR Art. 15: collect communication messages sent by the user."""
+        comm_messages = (
+            await db.execute(
+                select(CommMessage).where(
+                    CommMessage.sender_id == user_id,
+                    CommMessage.tenant_id == tenant_id,
+                ).limit(1000)
+            )
+        ).scalars().all()
+        return {
+            "comm_messages": [
+                {
+                    "id": str(m.id),
+                    "sender_type": m.sender_type,
+                    "content": m.content[:500],
+                    "created_at": m.created_at.isoformat() if m.created_at else None,
+                }
+                for m in comm_messages
+            ]
+        }
+
 
 # ─── self-registration ───