Implement member/payer filters on the Expenses List screen

[pedrazamiguez]

Problem / Motivation

Users need to find expenses paid by a specific person or involving specific members in the split, but no such filtering mechanism exists.

Proposed Solution

• Implement member/payer filters (e.g., dropdowns or chips) on the Expenses List screen.
• Filter the list to display only expenses where the selected member is the payer or is involved in the split.

Acceptance Criteria

• Member/payer filter UI is implemented and functional.
• Expenses list accurately filters based on selected member(s).
• All existing tests pass; new tests added where behaviour changes.
• make fast-check passes during iterative development (~15–30s).
• make check > build.log 2>&1 && echo "Check passed successfully" || (tail -n 100 build.log && exit 1) passes with 0 failures before merging.
• No new detekt findings introduced.

Out of Scope

• Advanced combination logic between payer and involved members (simple OR/AND depending on UX design is enough).

Related Issues / PRs

• Child of Track final stages of MVP development and release readiness #1401

[github-actions]

🌱 Branch created

feature/SPLTRP-1502

This branch has been automatically created based on develop.

🚀 Getting started

Fetch and switch to this branch with the latest changes from develop:

git fetch origin
git checkout feature/SPLTRP-1502
git pull origin develop

📌 When creating your PR

• Base branch: develop
• Title:

  [SPLTRP-1502]: Implement member/payer filters on the Expenses List screen
  

• Description: Closes #1502