refactor(block-h): resolve CommConversation hardcoding via kommunikation contract

app/plugins/builtins/kommunikation/services.py

@@ -1047,6 +1047,30 @@ async def _get_unread_count(
 # ─── Plugin Room Creation ───
 
 
+async def find_locked_room_id(
+    db: AsyncSession,
+    tenant_id: uuid.UUID,
+    plugin_name: str,
+    title: str,
+) -> uuid.UUID | None:
+    """Find the conversation ID of a locked plugin room by tenant and title.
+
+    Matches the same room semantics as ``create_plugin_room``: locked rooms
+    are owned by the plugin (``locked_by == plugin_name``) and soft-deleted
+    conversations are excluded. Returns ``None`` when no room exists.
+    """
+    result = await db.execute(
+        select(CommConversation.id).where(
+            CommConversation.tenant_id == tenant_id,
+            CommConversation.title == title,
+            CommConversation.is_locked.is_(True),
+            CommConversation.locked_by == plugin_name,
+            CommConversation.deleted_at.is_(None),
+        )
+    )
+    return result.scalar_one_or_none()
+
+
 async def create_plugin_room(
     db: AsyncSession,
     tenant_id: uuid.UUID,