Add Santander transactions data for analysis

[devin-ai-integration]

Add Santander transactions data for analysis

Summary

This PR adds the Santander transactions dataset to the data/ directory in both Excel and CSV formats. The Excel file was downloaded from the S3 bucket (devin-workshop.s3.eu-north-1.amazonaws.com/santander_transactions.xlsx) and converted to CSV using pandas for easier analysis.

The dataset contains 5,000 transaction records with 15 columns: transaction_id, customer_id, transaction_date, transaction_time, transaction_type, category, amount, currency, merchant_name, merchant_category_code, channel, location, is_international, is_recurring, and status.

Key data characteristics:

• 500 unique customers
• Date range: 2024-11-30 to 2025-11-30
• Transaction types: Debit (4,339) and Credit (661)
• 15 categories including Salary, Groceries, Utilities, Entertainment, etc.
• Amount range: £5.11 to £4,996.24 (total: £2.39M)

Review & Testing Checklist for Human

• Verify the Excel file is the correct one from the S3 bucket (spot-check a few rows)
• Confirm the CSV conversion preserved all 5,000 rows and 15 columns accurately
• Verify this is synthetic/sample data and does not contain real customer PII (note: dates are in the future, merchant names appear generated)

Notes

Requested by: Joao Esteves (joao.esteves@cognition.ai) / @joao-cognition

Link to Devin run: https://app.devin.ai/sessions/9dc4f6b13f60479ea17af5751fe0066a

[devin-ai-integration]

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