fix(types): align ParsePageRef TypedDict shape with its docstring

The docstring promises pageIndex/width/height are always populated and
only pageNumber may be absent, but the class was declared `total=False`,
which contradicts that and forces type-strict callers to guard every
subscript access on guaranteed-present fields. Switch to the default
(`total=True`) shape with pageNumber explicitly `NotRequired`, matching
the precedent set by ParseBounds in the same module.

No runtime impact — the wire already populates these fields.

Author: nickwinder

src/nutrient_dws/types/parse.py

@@ -12,7 +12,7 @@
 
 from typing import Literal
 
-from typing_extensions import TypedDict
+from typing_extensions import NotRequired, TypedDict
 
 from nutrient_dws.types.extraction_credits import ExtractionCredits
 
@@ -75,7 +75,7 @@ class ParseBounds(TypedDict):
     height: float
 
 
-class ParsePageRef(TypedDict, total=False):
+class ParsePageRef(TypedDict):
     """Reference to the page an element was extracted from.
 
     `pageIndex` and dimensions are always populated; `pageNumber` carries the
@@ -84,9 +84,9 @@ class ParsePageRef(TypedDict, total=False):
     """
 
     pageIndex: int
-    pageNumber: str
     width: float
     height: float
+    pageNumber: NotRequired[str]
 
 
 class ParseWord(TypedDict, total=False):