feat(cash): mark how a transaction was paid, exclude cash from reconciliation

getPendingReconciliations treated every unreconciled manual transaction as
awaiting a matching statement row. Cash never appears on a statement, so a cash
entry sat in the queue indefinitely being offered matches within 3 days and 1%
on amount - and accepting one is silently destructive: reconciled manual rows
are filtered out of every query, so the cash spend disappears while the card
transaction it matched claims to be that same spend.

Migration 0016 adds transactions.payment_method (card | cash | bank_transfer |
other, NULL = unknown) with a CHECK constraint and a partial index. The notCash()
fragment excludes cash from both halves of the reconciliation query - the pending
list and the candidate match subquery, which aliases the manual row as m.

Only cash is excluded. Bank transfers do appear on a statement now that
transaction accounts are imported, and NULL means unknown, so both stay
candidates and every pre-existing row behaves exactly as before.

ATM withdrawals deliberately stay categorised as spend rather than transfers.
Treating them as transfers is only correct if every cash purchase is logged;
with partial logging it silently deletes the unlogged remainder from spend.

src/lib/hooks.ts

@@ -104,6 +104,7 @@ export function useCreateTransaction() {
       transaction_type?: string;
       merchant_normalized?: string;
       category?: string;
+      payment_method?: string;
       splits?: { participant_id: number; share_percent: number }[];
     }) => {
       const res = await fetch("/api/transactions", {
@@ -140,6 +141,7 @@ export function useUpdateTransaction() {
       amount?: number;
       transaction_date?: string;
       trip_id?: number | null;
+      payment_method?: string | null;
     }) => {
       const res = await fetch(`/api/transactions/${id}`, {
         method: "PATCH",

src/lib/queries.ts

@@ -25,6 +25,9 @@ export interface TransactionRow {
   // loan repayment split — set only when the lender itemises it (migration 0014)
   principal_amount: number | null;
   interest_amount: number | null;
+  // How it was paid (migration 0016). NULL = unknown, treated as reconcilable.
+  // 'cash' is excluded from reconciliation — see notCash().
+  payment_method: string | null;
   // override fields
   category_override: string | null;
   merchant_override: string | null;
@@ -517,6 +520,22 @@ export async function batchInsertCSVTransactions(
   return txIds.length;
 }
 
+/**
+ * Excludes cash from reconciliation.
+ *
+ * Cash never appears on a statement, so a cash transaction would sit in the
+ * queue forever being offered matches within 3 days and 1% on amount. Accepting
+ * one is silently destructive: reconciled manual rows are filtered out of every
+ * query, so the cash spend vanishes while the card transaction it matched
+ * claims to be that same spend.
+ *
+ * Only cash is excluded. Bank transfers do appear on a statement now that
+ * transaction accounts are imported, and NULL means unknown — both stay
+ * candidates, which preserves the behaviour of every pre-existing row.
+ */
+export const notCash = (alias = "t") =>
+  `(${alias}.payment_method IS NULL OR ${alias}.payment_method <> 'cash')`;
+
 export interface PotentialMatch {
   id: number;
   transaction_date: string;
@@ -559,6 +578,7 @@ export async function getPendingReconciliations(ownerId: number): Promise<Manual
        WHERE ts.transaction_id = t.id
      ) txn_splits ON true
      WHERE t.statement_id IS NULL AND t.owner_id = $1 AND t.reconciled_with_id IS NULL
+       AND ${notCash("t")}
      ORDER BY t.transaction_date DESC, t.row_index ASC`,
     [ownerId]
   );
@@ -600,6 +620,7 @@ export async function getPendingReconciliations(ownerId: number): Promise<Manual
        WHERE m.statement_id IS NULL
          AND m.owner_id = $1
          AND m.reconciled_with_id IS NULL
+         AND ${notCash("m")}
          AND COALESCE(t.owner_id, s.owner_id) = $1
          AND NOT EXISTS (
            SELECT 1 FROM transactions mt WHERE mt.reconciled_with_id = t.id