* Add liability balance normalization logic with comprehensive tests
- Updated `SimplefinAccount::Processor` to normalize liability balances based on observed values, ensuring correct handling of debts and overpayments.
- Enhanced `SimplefinItem::Importer` to apply similar normalization rules during imports, improving consistency.
- Added multiple test cases in `SimplefinAccountProcessorTest` to validate edge cases for liabilities and mixed-sign scenarios.
- Introduced helper methods (`to_decimal`, `same_sign?`) to simplify numeric operations in normalization logic.
* Add overpayment detection for liabilities with heuristic-based classification
- Introduced `SimplefinAccount::Liabilities::OverpaymentAnalyzer` to classify liability balances as credit, debt, or unknown using transaction history.
- Updated `SimplefinAccount::Processor` and `SimplefinItem::Importer` to integrate heuristic-based balance normalization with fallback logic for ambiguous cases.
- Added comprehensive unit tests in `OverpaymentAnalyzerTest` to validate classification logic and edge cases.
- Enhanced logging and observability around classification results and fallback scenarios.
* Refactor liability handling for better fallback consistency
- Updated `sticky_key` method in `OverpaymentAnalyzer` to handle missing `@sfa.id` with a default value.
- Enhanced `SimplefinAccount::Processor` to use `with_indifferent_access` for `raw_payload` and `org_data`, improving robustness in liability type inference.
* Extract numeric helper methods into `SimplefinNumericHelpers` concern and apply across models
- Moved `to_decimal` and `same_sign?` methods into a new `SimplefinNumericHelpers` concern for reuse.
- Updated `OverpaymentAnalyzer`, `Processor`, and `Importer` to include the concern and remove redundant method definitions.
- Added empty fixtures for `simplefin_accounts` and `simplefin_items` to ensure test isolation.
- Refactored `OverpaymentAnalyzerTest` to reduce fixture dependencies and ensure cleanup of created records.
* Refactor overpayment detection logic for clarity and fallback consistency
- Simplified `enabled?` method in `OverpaymentAnalyzer` for clearer precedence order (Setting > ENV > default).
- Added `parse_bool` helper to streamline boolean parsing.
- Enhanced error handling with detailed logging for transaction gathering failures.
- Improved `sticky_key` method to use a temporary object ID fallback when `@sfa.id` is missing.
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Co-authored-by: Josh Waldrep <joshua.waldrep5+github@gmail.com>
* Add tests and logic for Simplefin account balance normalization
- Introduced `SimplefinAccountProcessorTest` to verify balance normalization logic.
- Updated `SimplefinAccount::Processor` to invert negative balances for liability accounts (credit cards and loans) while keeping asset balances unchanged.
- Added comments to clarify balance conventions and sign normalization rules.
* Refactor balances-only sync logic and improve tests for edge cases
- Updated `SimplefinItem::Importer` and `SimplefinItem::Syncer` to ensure `last_synced_at` remains nil during balances-only runs, preserving chunked-history behavior for full syncs.
- Introduced additional comments to clarify balances-only implications and syncing logic.
- Added test case in `SimplefinAccountProcessorTest` to verify correct handling of overpayment for credit card liabilities.
- Refined balance normalization in `SimplefinAccount::Processor` to always invert liability balances for consistency.
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Co-authored-by: Josh Waldrep <joshua.waldrep5+github@gmail.com>
