# 20 — Dashboard composition (single-dashboard MVP)

## Goal

Each user sees a single default dashboard with widgets pre-seeded from the registry. Every widget is rendered with a `config` (per the task 04 contract). No customization yet — task 25/26 add multiple dashboards and the editor.

## Why

Lands a working dashboard quickly so the app is usable while the customization layer is built. Validates the configurable widget contract end-to-end. The schema introduced here (one row per user) gets generalized in task 25 to support many dashboards per user.

## Depends on

- 10 (calendar), 11 (lists), 12 (notes)

## Scope

### Schema (interim, generalized in task 25)

Add a `default_dashboard_layout` jsonb column on `users`. Shape:

```jsonc
{
  "version": 1,
  "widgets": [
    {
      "widgetId": "calendar.upcoming",
      "config": { "calendarIds": "all", "days": 3 },
      "x": 0,
      "y": 0,
      "w": 6,
      "h": 3,
    },
    {
      "widgetId": "lists.list",
      "config": { "listIds": "all", "showCompleted": false },
      "x": 6,
      "y": 0,
      "w": 6,
      "h": 3,
    },
  ],
}
```

If null, fall back to the registry's default seed (sorted by `defaultPriority`, packed by `defaultSize`).

### Layout

- 12-col responsive grid using basic CSS Grid (no drag library yet — task 26 introduces it).
- Mobile: single column ordered by `y` then `x`.
- Each widget is a server component that receives `config` and renders inside a card. Suspense boundary per widget so they load in parallel.

### Seeded widgets the registry must contribute

These are widget definitions, not hardcoded slots:

- `calendar.upcoming` (calendar module)
- `calendar.month` (calendar module)
- `lists.list` (lists module)
- `notes.filtered` (notes module)
- `core.activity` (\_core; depends on task 22 — until then render a placeholder card)

### Header

- Page title "Dashboard".
- "+" floating action button opens the quick-add menu (task 21).
- _No_ edit-mode toggle yet — that lands in task 26.

## Out of scope

- Multiple dashboards (task 25).
- Drag, resize, picker, configure UI (task 26).
- User-configurable widget order. Defaults are taken from `defaultPriority`.

## Acceptance criteria

- [ ] First-time user lands on a populated dashboard with widgets seeded from the registry's `defaultPriority` + `defaultSize`.
- [ ] Every widget receives a typed `config` and renders without `if (widgetId === ...)` branches in the dashboard code.
- [ ] Removing a module from `src/modules/index.ts` cleanly removes its widgets — no errors, no blank slot.
- [ ] Widgets load in parallel (verify in network tab — no waterfall).
- [ ] Mobile (375px) is usable without horizontal scroll.
- [ ] The schema column added here has a clean migration path to the `dashboards` table introduced in task 25 (a one-line copy-into-default-dashboard migration is enough).