Update app labels for billing, writer, and planner models; fix foreign key references in automation migrations

- Set app labels for CreditTransaction and CreditUsageLog models to 'billing'.
- Updated app labels for Tasks, Content, and Images models to 'writer'.
- Changed foreign key references in automation migrations from 'account' to 'tenant' for consistency.

backend/igny8_core/business/planning/models.py

@@ -15,6 +15,7 @@ class Clusters(SiteSectorBaseModel):
     updated_at = models.DateTimeField(auto_now=True)
     
     class Meta:
+        app_label = 'planner'
         db_table = 'igny8_clusters'
         ordering = ['name']
         verbose_name = 'Cluster'
@@ -74,6 +75,7 @@ class Keywords(SiteSectorBaseModel):
     updated_at = models.DateTimeField(auto_now=True)
     
     class Meta:
+        app_label = 'planner'
         db_table = 'igny8_keywords'
         ordering = ['-created_at']
         verbose_name = 'Keyword'
@@ -178,6 +180,7 @@ class ContentIdeas(SiteSectorBaseModel):
     updated_at = models.DateTimeField(auto_now=True)
     
     class Meta:
+        app_label = 'planner'
         db_table = 'igny8_content_ideas'
         ordering = ['-created_at']
         verbose_name = 'Content Idea'