Replace BaseModels with dataclasses in _format

These classes do not need to be serializable and the dynamic creation
of generic classes does not play nicely with both pyright strict and
pydantic with the current class hierarchy. This could be refactored
in future to separate dynamic class creation from generic class
parameterization.

src/pvi/_format/screen.py

@@ -1,13 +1,12 @@
 from __future__ import annotations
 
 from collections.abc import Iterator, Sequence
+from dataclasses import dataclass, field
 from typing import (
     Generic,
     TypeVar,
 )
 
-from pydantic import BaseModel, Field
-
 from pvi._format.utils import Bounds
 from pvi._format.widget import (
     GroupFormatter,
@@ -41,30 +40,26 @@
 T = TypeVar("T")
 
 
-class ScreenLayout(BaseModel):
-    spacing: int = Field(description="Spacing between widgets")
-    title_height: int = Field(description="Height of screen title bar")
-    max_height: int = Field(description="Max height of the screen")
-    group_label_height: int = Field(description="Height of the group title label")
-    label_width: int = Field(description="Width of the labels describing widgets")
-    widget_width: int = Field(description="Width of the widgets")
-    widget_height: int = Field(
-        description="Height of the widgets (Labels use this too)"
-    )
-    group_widget_indent: int = Field(
-        0, description="Indentation of widgets within groups. Defaults to 0"
-    )
-    group_width_offset: int = Field(
-        0, description="Additional border width when using group objects. Defaults to 0"
-    )
+@dataclass
+class ScreenLayout:
+    spacing: int
+    title_height: int
+    max_height: int
+    group_label_height: int
+    label_width: int
+    widget_width: int
+    widget_height: int
+    group_widget_indent: int
+    group_width_offset: int
 
 
-class ScreenFormatterFactory(BaseModel, Generic[T]):
+@dataclass
+class ScreenFormatterFactory(Generic[T]):
     screen_formatter_cls: type[GroupFormatter[T]]
     group_formatter_cls: type[GroupFormatter[T]]
     widget_formatter_factory: WidgetFormatterFactory[T]
     layout: ScreenLayout
-    components: dict[str, ComponentUnion] = Field(default={}, init_var=False)
+    components: dict[str, ComponentUnion] = field(default_factory=dict)
     base_file_name: str = ""
 
     def create_screen_formatter(

src/pvi/_format/widget.py

@@ -1,13 +1,12 @@
 from __future__ import annotations
 
 from collections.abc import Callable
+from dataclasses import dataclass, field
 from enum import StrEnum
 from typing import Any, Generic, TypeVar
 
 from typing_extensions import Self
 
-from pydantic import BaseModel, Field, create_model
-
 from pvi._format.utils import Bounds
 from pvi.device import (
     LED,
@@ -79,7 +78,8 @@ def create_group(
         raise NotImplementedError(self)
 
 
-class WidgetFormatter(BaseModel, Generic[T]):
+@dataclass
+class WidgetFormatter(Generic[T]):
     bounds: Bounds
 
     def format(self) -> list[T]:
@@ -132,23 +132,26 @@ def format(self: WidgetFormatter[T]) -> list[T]:
                 )
             ]
 
-        return create_model(
+        return type(  # type: ignore
             f"""{cls.__name__}<{search.strip('"')}>""",
-            __base__=cls,
-            format=format,
+            (cls,),
+            {"format": format},
         )
 
 
+@dataclass
 class LabelWidgetFormatter(WidgetFormatter[T]):
     text: str
     description: str = ""
 
 
+@dataclass
 class PVWidgetFormatter(WidgetFormatter[T]):
     pv: str
     widget: WidgetUnion
 
 
+@dataclass
 class ActionWidgetFormatter(WidgetFormatter[T]):
     label: str
     pv: str
@@ -159,18 +162,20 @@ def tooltip(self) -> str:
         return f"{self.pv} = {self.value}"
 
 
+@dataclass
 class SubScreenWidgetFormatter(WidgetFormatter[T]):
     label: str
     file_name: str
     components: Group | None = None
-    macros: dict[str, str] = Field(default={})
+    macros: dict[str, str] = field(default_factory=dict)
 
 
 class GroupType(StrEnum):
     GROUP = "GROUP"
     SCREEN = "SCREEN"
 
 
+@dataclass
 class GroupFormatter(WidgetFormatter[T]):
     bounds: Bounds
     title: str
@@ -180,7 +185,7 @@ def format(self) -> list[T]:
         """Instances should be created using `from_template`, which defines `format`"""
         raise NotImplementedError(self)
 
-    def model_post_init(self, _context: Any) -> None:
+    def __post_init__(self) -> None:
         self.resize()
 
     def resize(self):
@@ -259,15 +264,15 @@ def resize(self: GroupFormatter[T]):
             )
             pass
 
-        return create_model(
+        return type(  # type: ignore
             f"{cls.__name__}<{search}>",
-            __base__=cls,
-            format=format,
-            resize=resize,
+            (cls,),
+            {"format": format, "resize": resize},
         )
 
 
-class WidgetFormatterFactory(BaseModel, Generic[T]):
+@dataclass
+class WidgetFormatterFactory(Generic[T]):
     header_formatter_cls: type[LabelWidgetFormatter[T]]
     label_formatter_cls: type[LabelWidgetFormatter[T]]
     led_formatter_cls: type[PVWidgetFormatter[T]]