US-5.7not implemented Show a correlation matrix of combined-account payments
As a user who sometimes pays with split payments (e.g. part card, part cash) I want see an N x N correlation matrix showing which accounts were used together in combined payments and how much was spent from each so that I can understand my payment patterns across accounts.
Acceptance Criteria
- The matrix is N x N where N = number of accounts (bank accounts + wallets).
- Each cell (i, j) shows the total amount where account i and account j were both used on the same receipt.
- Amounts are shown in their respective currencies.
- A fractional matrix variant shows the percentage of total spending per account (e.g. "for receipts involving both Triodos and Wallet, 65% came from Triodos and 35% from Wallet").
- Diagonal cells show the total spent from each account across all receipts (including single-account payments).
No DAG diagram: Not yet implemented — analytical visualisation on the journal layer; reads transaction data but introduces no new data-flow path.
Demo video coming soon