feat(M2): Persönliche Dashboards — Tabelle, CRUD, Lazy-Seed, RLS (#360)

- dashboards-Tabelle (Layout JSONB, Tabs, is_default, partial unique name index)
- 6 CRUD-Endpoints /api/v1/dashboards, Owner-only (saved_views-Präzedenz), Audit
- Lazy Default-Seed aus MiniApp-Registry (permission-gefiltert, 12-Spalten-Flow)
- CORE_PERMISSIONS dashboard:read/write (fixt Phantom-Permission in dashboard.py)
- Migration 0144: RLS crm_api+crm_worker + konvergenter Fix der 3 Phase-L-Policies
- Tests: test_dashboards_backend.py 23/23 (TDD rot->grün); Regression 162/163

app/models/__init__.py

@@ -17,12 +17,13 @@ from app.models.contact_folder import ContactFolder
 from app.models.contact_merge import ContactMergeHistory
 from app.models.currency import Currency
 from app.models.custom_field_definition import CustomFieldDefinition
+from app.models.dashboard import Dashboard
 from app.models.entity_history import EntityHistory
 from app.models.entity_permission import EntityPermission
 from app.models.entity_policy import EntityPolicy
 from app.models.group import Group, UserGroup
 from app.models.notification import Notification, NotificationPreference, NotificationType
-from app.models.outbox import EventOutbox, OutboxDelivery
+from app.models.outbox import EventOutbox, OutboxDelivery  # noqa: F401
 from app.models.owned_mixin import OwnedMixin
 from app.models.permission_delegation import PermissionDelegation
 from app.models.permission_template import PermissionTemplate
@@ -80,6 +81,7 @@ __all__ = [
     "WorkflowInstance",
     "WorkflowStepHistory",
     "SavedView",
+    "Dashboard",
 ]
 from app.models.entity_attachment import EntityAttachment  # noqa: F401
 from app.models.workspace import (  # noqa: F401