# Groups + Switcher Plan

## Focus
Group create/join + group switcher in navbar.

## Goals
- Create groups and invite codes.
- Join groups via invite code.
- Persist active group selection per user.
- Enforce server-side group membership checks.

## Proposed changes
### Database (existing schema)
Use existing tables:
- `groups`, `group_members`.

### Backend
Add routes:
- `POST /api/groups` to create a group
  - Body: `{ name }`
  - Creates group, generates invite code, adds creator as GROUP_ADMIN.
- `POST /api/groups/join` to join by invite code
  - Body: `{ inviteCode }`
  - Adds user as MEMBER if not already in group.
- `GET /api/groups` to list groups for current user
  - Returns list of groups and roles.
- `POST /api/groups/active` to set active group
  - Persists in `user_settings` JSON.

Add server helpers:
- `getSessionUser()` already exists
- Add `requireSessionUser()` and `getUserGroups(userId)` helpers
- Add `getActiveGroup(userId)` helper

### Frontend
- Update navbar to show current group and dropdown of groups.
- Add minimal create/join UI (modal or simple dropdown actions).

### Tests
- Add API tests for create/join/list/active group.

## Files impacted (expected)
- `apps/web/app/api/groups/*`
- `apps/web/lib/groups.ts`
- `apps/web/components/navbar.tsx`
- `apps/web/app/page.tsx` (use active group)
- `apps/web/__tests__/groups.test.ts`

## Status
- Implemented

## Test output
- `create group inserts membership`