feat: validate annotation-type before returning

this avoids breaking the whole chart due to annotations.

docs/strategy-callbacks.md

@@ -1172,11 +1172,12 @@ class AwesomeStrategy(IStrategy):
 
 ```
 
+Entries will be validated, and won't be passed to the UI if they don't correspond to the expected schema and will log an error if they don't.
+
 !!! Warning "Many annotations"
     Using too many annotations can cause the UI to hang, especially when plotting large amounts of historic data.
     Use the annotation feature with care.
 
-
 ### Plot annotations example
 
 ![FreqUI - plot Annotations](assets/frequi-chart-annotations-dark.png#only-dark)

freqtrade/ft_types/plot_annotation_type.py

@@ -1,14 +1,18 @@
 from datetime import datetime
 from typing import Literal
 
-from pydantic import BaseModel
+from pydantic import TypeAdapter
+from typing_extensions import Required, TypedDict
 
 
-class AnnotationType(BaseModel):
-    type: Literal["area"]
-    start: None | str | datetime = None
-    end: None | str | datetime = None
-    y_start: None | float = None
-    y_end: None | float = None
-    color: None | str = None
-    label: None | str = None
+class AnnotationType(TypedDict, total=False):
+    type: Required[Literal["area"]]
+    start: str | datetime
+    end: str | datetime
+    y_start: float
+    y_end: float
+    color: str
+    label: str
+
+
+AnnotationTypePA = TypeAdapter(AnnotationType)

freqtrade/strategy/interface.py

@@ -1812,12 +1812,16 @@ class IStrategy(ABC, HyperStrategyMixin):
                 start_date=dataframe.iloc[0]["date"].to_pydatetime(),
                 end_date=dataframe.iloc[-1]["date"].to_pydatetime(),
             )
-            annotations_new = []
+
+            from freqtrade.ft_types.plot_annotation_type import AnnotationTypePA
+
+            annotations_new: list[AnnotationType] = []
             for annotation in annotations:
                 if isinstance(annotation, dict):
                     # Convert to AnnotationType
                     try:
-                        annotations_new.append(AnnotationType(**annotation))
+                        AnnotationTypePA.validate_python(annotation)
+                        annotations_new.append(annotation)
                     except ValidationError as e:
                         logger.error(f"Invalid annotation data: {annotation}. Error: {e}")
                 else: