🧹 cleanup redundant getattr checks in JudgeAgent

[ishaanxgupta]

This change improves the code health of the JudgeAgent by relying on the BaseVectorStore interface contract instead of using runtime getattr checks for abstract methods.

Key changes:

1. Interface Formalization: Added search_by_text as an @abstractmethod in BaseVectorStore. This ensures all vector store implementations provide this convenience method, which is already used by the JudgeAgent.
2. Code Simplification: Removed redundant getattr checks for search_by_metadata and search_by_text in src/agents/judge.py. This also allowed removing a fallback to semantic search that was previously used when search_by_metadata was missing, simplifying the logic.
3. Documentation Update: Updated PineconeVectorStore docstrings and comments to reflect the updated interface contract.
4. Linting: Fixed unused imports in src/storage/base.py identified by ruff.

These changes make the code more maintainable, readable, and type-safe by enforcing a consistent interface across the vector storage layer.

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PR created automatically by Jules for task 10208529608654575702 started by @ishaanxgupta

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[ishaanxgupta]

@ved015 please review this one