# 25 — Multiple dashboards per user

## Goal

Each user can create any number of named dashboards, switch between them, and choose one as their default. No customization mechanic yet — that's task 26.

## Why

Decouples "the dashboard" from "user's home page". A user might have a _Daily_, _Garden_, and _Wedding planning_ dashboard, each composing different widgets. This task introduces the entity; task 26 adds the editor.

## Depends on

- 20 (single-dashboard MVP — provides the layout shape we generalize from)

## Scope

### Schema

```sql
CREATE TABLE dashboards (
  id uuid PRIMARY KEY,
  user_id uuid REFERENCES users(id) ON DELETE CASCADE,
  name text NOT NULL,
  slug text NOT NULL,             -- url-safe, unique per user
  is_default boolean NOT NULL DEFAULT false,
  position int NOT NULL DEFAULT 0,
  layout jsonb NOT NULL DEFAULT '{"version":1,"widgets":[]}',
  created_at timestamptz NOT NULL DEFAULT now(),
  updated_at timestamptz NOT NULL DEFAULT now()
);

CREATE UNIQUE INDEX dashboards_user_slug_uq ON dashboards (user_id, slug);
CREATE UNIQUE INDEX dashboards_user_default_uq
  ON dashboards (user_id) WHERE is_default;
```

Migration also copies each user's `default_dashboard_layout` (from task 20) into a single dashboard row named "Home" with `is_default = true`, then drops the `users.default_dashboard_layout` column.

### Routes

- `/` — redirect to the user's default dashboard (`/d/<default-slug>`).
- `/d/[slug]` — render that dashboard. 404 if the slug doesn't belong to the current user. Layout rendering is unchanged from task 20 (still no edit mode).

### Server actions

- `createDashboard({ name })` — generates a slug from the name (collision-suffixed); empty layout; not default.
- `renameDashboard(id, name)` — also re-derives slug if name changes (or keeps slug stable; pick stable, document it).
- `deleteDashboard(id)` — disallowed if it's the user's only dashboard. If it was default, mark another as default before deleting.
- `setDefaultDashboard(id)` — flip flags within a transaction.
- `reorderDashboards(orderedIds)` — bulk update `position`.

All gated on `dashboards.user_id = currentUserId`.

### UI

- **Switcher in the app header** — desktop: tabs strip with the user's dashboards in `position` order, an active indicator, a "+ new" tab at the end, and a kebab on the active tab for rename / set default / delete. Mobile: dropdown with the same actions.
- **`/settings/dashboards`** — full management view: drag to reorder (use the same library task 26 will pull in, or a small `dnd-kit` setup — leave a note for task 26 to consolidate).
- New-dashboard flow: prompts for a name, creates an empty dashboard, navigates to it. Empty state explains "this dashboard has no widgets yet — task 26 will add the picker." (Or, if 26 has landed, just "Add widget".)

## Out of scope

- Drag / resize / picker / configure (task 26).
- Sharing dashboards with the household or via share-link (deferred; nullable `household_id` later).
- Per-device or per-orientation layouts.

## Acceptance criteria

- [ ] Migration moves every existing user to a single `Home` dashboard with `is_default = true`. Idempotent.
- [ ] User can create, rename, reorder, delete dashboards; cannot delete their last one; cannot have two defaults.
- [ ] `/` redirects to the user's default dashboard's `/d/<slug>`.
- [ ] Switcher renders in the header on both desktop and mobile, scoped to the current user only.
- [ ] Server actions reject any operation against a dashboard the caller doesn't own.
- [ ] No regression in task 20's layout rendering — existing widgets render identically inside the new route.