Use borsh::object_length to reserve the exact serialized size for OraclePriceAccount data without relying on size_of_val.
Add coverage for string-backed source identifiers.
Add shared oracle_core price-feed types and account-backed validation.
Wire stablecoin to re-export the shared oracle interface and add the mock_oracle program plus IDL artifact.
Update ATA integration tests for the current Transfer instruction shape.
Refs #96