feat: add dashboard API with quick links and widgets

- Dashboard domain with Quick Links CRUD + reorder endpoints
- Dashboard widgets management endpoints
- Database migrations for quick_links and dashboard_widgets tables
- Static file controller for Organizr widgets
- Default local user when OIDC is disabled
- Domain-based architecture refactor (src/domains/, src/shared/)
- Test suite updated for new structure (285 tests passing)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/shared/base.py

@@ -0,0 +1,65 @@
+"""
+Base classes for Core-API
+
+Provides common base classes for controllers and schemas.
+"""
+from datetime import datetime
+from typing import Any
+from abc import ABC, abstractmethod
+from fastapi import APIRouter
+from pydantic import BaseModel, ConfigDict
+
+
+class BaseController(ABC):
+    """
+    Base controller class with common functionality
+
+    All controllers should inherit from this class and implement
+    the create_router() method to define their endpoints.
+    """
+
+    def __init__(self, prefix: str, tags: list[str]):
+        """
+        Initialize base controller
+
+        Args:
+            prefix: URL prefix for this controller's routes
+            tags: OpenAPI tags for documentation grouping
+        """
+        self.prefix = prefix
+        self.tags = tags
+        self._router = None
+
+    @abstractmethod
+    def create_router(self) -> APIRouter:
+        """Create and configure the FastAPI router for this controller"""
+        pass
+
+    @property
+    def router(self) -> APIRouter:
+        """Get the router instance, creating it if needed"""
+        if self._router is None:
+            self._router = self.create_router()
+        return self._router
+
+
+class BaseSchema(BaseModel):
+    """
+    Base Pydantic model with standardized configuration
+
+    All schemas should inherit from this to ensure consistent behavior.
+    """
+
+    model_config = ConfigDict(
+        strict=False,
+        populate_by_name=True,
+        use_enum_values=True,
+        validate_assignment=True,
+        json_encoders={
+            datetime: lambda v: v.isoformat() if v else None
+        }
+    )
+
+    def dict_without_none(self) -> dict[str, Any]:
+        """Return model as dict, excluding None values"""
+        return {k: v for k, v in self.model_dump().items() if v is not None}