feat(08-03): FavoriteLink schema + FavoritesModule (CRUD + SSRF icon discovery)

- Add FavoriteLink Prisma model (userId/tenantId/widgetId scope, iconUrl nullable, position)
- IconDiscoveryService: port SSRF-protected icon discovery with redirect: 'manual',
  private IP / blocked-hostname checks, 4000ms timeout, 200k HTML cap (T-08-05)
- FavoritesService: list/create/update/remove all scoped by userId (T-08-06 / Pitfall 3)
- FavoritesController: GET /favorites?widgetId, POST, PATCH :id, DELETE :id
- FavoritesModule registered in AppModule
- tsc --noEmit passes for @tessera/api

apps/api/src/favorites/dto/create-favorite.dto.ts

@@ -0,0 +1,32 @@
+import {
+  IsInt,
+  IsNotEmpty,
+  IsOptional,
+  IsString,
+  IsUrl,
+  IsUUID,
+} from 'class-validator';
+
+/**
+ * DTO for creating a new FavoriteLink.
+ * widgetId scopes the link to a specific widget instance (T-08-06 / Pitfall 3).
+ */
+export class CreateFavoriteDto {
+  @IsUUID()
+  widgetId!: string;
+
+  @IsString()
+  @IsNotEmpty()
+  title!: string;
+
+  @IsUrl()
+  url!: string;
+
+  @IsOptional()
+  @IsString()
+  iconUrl?: string;
+
+  @IsOptional()
+  @IsInt()
+  position?: number;
+}