chore(context): refactor for consistency, optimize formatting, and simplify logic

- Cleaned up unnecessary comments in `__all__` definitions for better readability.
- Adjusted indentation and formatting across modules for improved clarity (e.g., long lines, logical grouping).
- Simplified conditional expressions and inline comments for context scoring and ranking.
- Replaced some hard-coded values with type-safe annotations (e.g., `ClassVar`).
- Removed unused imports and ensured consistent usage across test files.
- Updated `test_score_not_cached_on_context` to clarify caching behavior.
- Improved truncation strategy logic and marker handling.

backend/app/services/context/adapters/base.py

@@ -5,7 +5,7 @@ Abstract base class for model-specific context formatting.
 """
 
 from abc import ABC, abstractmethod
-from typing import Any
+from typing import Any, ClassVar
 
 from ..types import BaseContext, ContextType
 
@@ -19,7 +19,7 @@ class ModelAdapter(ABC):
     """
 
     # Model name patterns this adapter handles
-    MODEL_PATTERNS: list[str] = []
+    MODEL_PATTERNS: ClassVar[list[str]] = []
 
     @classmethod
     def matches_model(cls, model: str) -> bool:
@@ -125,7 +125,7 @@ class DefaultAdapter(ModelAdapter):
     Uses simple plain-text formatting with minimal structure.
     """
 
-    MODEL_PATTERNS: list[str] = []  # Fallback adapter
+    MODEL_PATTERNS: ClassVar[list[str]] = []  # Fallback adapter
 
     @classmethod
     def matches_model(cls, model: str) -> bool: