finanzen/backlog/tasks/task-4 - Add-selection-total-to-transactions.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, priority, ordinal

id	title	status	assignee	created_date	updated_date	labels	dependencies	priority	ordinal
TASK-4	Add selection total to transactions	In Progress		2026-06-15 19:21	2026-06-15 19:24			high	4000

Description

Add table selection controls on the transactions page so visible/filtered rows can be selected in bulk and the sum of selected transaction amounts is shown.

Acceptance Criteria

• #1 A select-all control can select and clear all currently visible filtered transactions
• #2 Individual row selection continues to work alongside the select-all control
• #3 The UI displays the count and formatted euro total of selected transactions
• #4 Automated tests cover bulk selection and selected-total behavior

Implementation Plan

1. Inspect current transaction table selection behavior
2. Add failing coverage for select-all and selected sum
3. Implement visible-row bulk selection and selected total UI
4. Run focused tests/build and update acceptance criteria

Implementation Notes

Added failing Vitest coverage for visible bulk selection and selected totals, then implemented transactionsSelection helpers and wired TransactionsPage header checkbox plus selected count/sum. Focused test and build pass. Global lint currently fails on pre-existing unrelated lint errors in Convex/generated/UI files.