Close local release-quality gaps and reconcile workplan status

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a0e332-3365-77c0-8491-084e9ea33ac1

llm_connect/problem_classes.py

@@ -6,7 +6,6 @@ from collections.abc import Mapping, Sequence
 from dataclasses import dataclass
 from typing import Any, Protocol
 
-
 DEFAULT_WORDS_PER_TOKEN = 0.75
 
 
@@ -66,7 +65,7 @@ class ProblemClass(Protocol):
         observations: Sequence[Any],
         *,
         min_observations: int = 3,
-    ) -> "ProblemClass":
+    ) -> ProblemClass:
         """Return an estimator with params adapted from observed token use."""
         ...
 
@@ -99,7 +98,7 @@ class ProblemClassRegistry:
         self._classes[name] = problem_class
 
     @classmethod
-    def default(cls) -> "ProblemClassRegistry":
+    def default(cls) -> ProblemClassRegistry:
         """Return the built-in problem-class registry."""
         return cls(
             [