[type-safety] Push ArtifactKind/ArtifactStatus discriminated unions through Filters widget

[fedorovvvv]

Source: PRD-018 SC-2 audit, Type [W1].

template/src/widgets/artifact-filters/ui/Filters.svelte:5-15

let {
  kinds = [],
  status = [],
  kindFilter = $bindable(new Set<string>()),
  statusFilter = $bindable(new Set<string>()),
  ...
} = $props();

The widget exists to filter by kind and status, both of which are discriminated string unions defined in entities/artifact/model/types.ts (ArtifactKind, ArtifactStatus). Typing them as string[] / Set<string> throws away exhaustiveness:

• A <ToggleGroup type="multiple"> could fire any string and the parent silently accepts it.
• HomePage's n.kind.toLowerCase() returns string and there's no guard that the lowercased form is one of the canonical kinds.

Fix

• Tighten Filter props: kinds?: ArtifactKind[]; kindFilter?: Set<ArtifactKind> (analogous for status).
• Either:
  • Make Filters accept the canonical-cased kinds and lowercase only at presentation, OR
  • Declare type LowercaseArtifactKind = Lowercase<ArtifactKind> and use it consistently.

Acceptance

• npm run check clean.
• A wrong-cased kind passed to Filters is a compile error.
• Exhaustiveness check on kindLabel(k) / kindColor(k) lights up if ArtifactKind grows.

Related

• Type-safety [W7] in HomePage breach loop — same exhaustiveness gap, can be fixed in this issue or separately.

Audit traceability

• Reviewer: TypeScript-pro

[fedorovvvv]

Fixed in branch `develop` as part of PRD-019 Wave 3.

What changed

`template/src/widgets/artifact-filters/ui/Filters.svelte`:
```ts
import type { ArtifactKind, ArtifactStatus } from '@/entities/artifact';

interface Props {
kinds?: ArtifactKind[];
statuses?: ArtifactStatus[];
kindFilter?: Set;
statusFilter?: Set;
}
```
`onValueChange` callbacks cast the bits-ui-emitted `string[]` to `ArtifactKind[]` / `ArtifactStatus[]` since values originate from the typed `kinds` / `statuses` arrays this widget owns.

`template/src/pages/home/ui/HomePage.svelte`:

• `kindFilter` / `statusFilter` retyped to `Set` / `Set`.
• Local `toLowerKinds` / `toLowerStatuses` helpers replace brute `.toLowerCase()` — they validate via `isArtifactKind` / `isArtifactStatus` type guards.

`template/src/pages/home/lib/settings.ts`:

• `PersistedSettings` and `ResolvedSettings` retyped accordingly.
• `loadSettings` filters incoming JSON via the same type guards — corrupt or out-of-spec values are silently dropped instead of poisoning the typed Set.

Acceptance

• `npm run check` clean.
• A wrong-cased kind passed to Filters is a compile error (try `<Filters kinds={['PRD']}>` — TypeScript rejects).
• Exhaustiveness check on `kindLabel(k)` / `kindColor(k)` lights up if `ArtifactKind` grows.

[fedorovvvv]

Resolved by PR #100 (merged into develop as merge commit 6f498b9). Will reach main with the next release/v* cycle.