Feature: Adding Product Service to Lunar

This commit introduces a Product service to Lunar. This product service calls Meilisearch to fetch an indexed product. The indexer has been updated to also include the collection and the price of the product.

A product search service has also been created to be used by the frontend's search

docs/product-listing.md

@@ -0,0 +1,122 @@
+# Product Listing
+
+`Modules\Core\Catalog\ProductService` provides browsing/filtering of the product catalog
+(list all, filter by collection/brand/price range) for a storefront, reading directly from the
+Meilisearch index rather than the database.
+
+This is separate from `Modules\Core\Search\ProductSearchService` (see `product-search.md`), which
+handles free-text query search. `ProductService` is for browsing without a search term.
+
+---
+
+## Why it reads from the index, not the database
+
+`ProductService::list()` calls `Product::search('')->paginateRaw(...)` and returns the raw
+Meilisearch hits directly — it never calls Scout's `->get()`, which would re-hydrate Eloquent
+models from the database per result. This avoids an extra database round-trip on every listing
+request, but it means **callers only get whatever fields are in the indexed document**, not the
+full `Product` model or its relations.
+
+A single-product detail view needs the full record (all attributes, media, variants, etc.) and
+should look the product up directly via `Lunar\Models\Product`, not through `ProductService`.
+
+---
+
+## Usage
+
+```php
+use Modules\Core\Catalog\ProductFilters;
+use Modules\Core\Catalog\ProductService;
+
+$service = app(ProductService::class);
+
+// List everything, paginated
+$result = $service->list(perPage: 24, page: 1);
+
+// Filter by collection, brand, and/or price range
+$result = $service->list(
+    filters: new ProductFilters(collectionId: 17, minPrice: 10.0, maxPrice: 50.0),
+    perPage: 24,
+    page: 1,
+);
+
+$result['data'];               // array of Meilisearch documents (plain arrays, not models)
+$result['meta']['total'];
+$result['meta']['per_page'];
+$result['meta']['current_page'];
+$result['meta']['last_page'];
+```
+
+All `ProductFilters` fields are optional; only the ones set are added to the Meilisearch query.
+
+---
+
+## Fields this depends on: `Modules\Core\Search\ProductIndexer`
+
+Lunar's own `Lunar\Search\ProductIndexer` doesn't index collection membership or a comparable
+price, and only marks `__soft_deleted`, `skus`, `status` as filterable — none of what
+`ProductFilters` needs. `Modules\Core\Search\ProductIndexer` extends it to add:
+
+| Field | Source | Notes |
+|---|---|---|
+| `collections` | `$product->collections->pluck('id')` | Array of collection IDs (as strings). Filtering matches by ID, not slug — the caller resolves whichever collection it means before calling `ProductService`. |
+| `price` | Cheapest variant's base price | Float in major units (e.g. `19.99`, not `1999`). Base price only — no customer group, default currency (`Currency::getDefault()`) only. `null` if the product has no priced variant yet, so it's excluded from range filters rather than treated as free. |
+| `brand` | Already indexed by Lunar's base indexer | Newly marked **filterable** — it existed in the document already, just wasn't usable in a `filter` clause. |
+
+`description` and other translated attributes are indexed as-is, including any HTML markup
+(e.g. from a Shopify `Body (HTML)` import) — **not stripped**. Any view rendering a description
+sourced from `ProductService`'s results must treat it as trusted HTML.
+
+---
+
+## Multi-variant products and price
+
+A product's `price` is its *cheapest* variant's price ("from €19.99" style), not every variant's
+price. A price-range filter matches based on that single minimum — a product with one cheap
+variant and several expensive ones will match a low-price-range filter even though most of its
+variants don't.
+
+---
+
+## Registering the indexer
+
+Not automatic — an app opts in via its own `config/lunar/search.php`:
+
+```php
+'indexers' => [
+    Lunar\Models\Product::class => Modules\Core\Search\ProductIndexer::class,
+    // ...other model indexers unchanged
+],
+```
+
+## Re-syncing after this change
+
+Filterable attributes are Meilisearch index settings, not computed per-query — changing them
+requires re-syncing settings and reindexing existing documents:
+
+```bash
+php artisan lunar:meilisearch:setup
+php artisan lunar:search:index "Lunar\Models\Product" --refresh
+```
+
+**If `SCOUT_QUEUE=true`, restart the queue worker after deploying an indexer change.** A running
+`queue:work` process loads PHP classes once at boot and keeps that code in memory for its entire
+lifetime — it does not pick up an edited/newly-deployed indexer class. Symptoms: reindexing
+commands succeed with no errors, `Product::toSearchableArray()` returns the new fields correctly
+when called directly (e.g. via `artisan tinker`, which always boots fresh), but documents written
+via `$model->searchable()` through the live queue are still missing the new fields. Restarting the
+queue worker (`docker compose restart queue`, or equivalent) resolves it — no code change needed.
+
+---
+
+## Meilisearch driver quirk: `paginateRaw()`'s `items()` is not a list of hits
+
+For the Meilisearch engine specifically, Scout's `Builder::paginateRaw()` puts the **entire raw
+response** (`hits`, `query`, `processingTimeMs`, `hitsPerPage`, `page`, `totalPages`, `totalHits`)
+into the paginator's `items()`, not a plain array of documents. Calling `$paginator->items()`
+and treating it as a list (e.g. `collect($paginator->items())->values()`) silently produces a
+7-element array whose first element happens to be the real hits and the rest are stray scalars
+from the other response keys — no error, just wrong data leaking into what looks like a normal
+list. `ProductService::list()` pulls `$paginator->items()['hits']` explicitly to avoid this;
+`$paginator->total()`/`perPage()`/`currentPage()`/`lastPage()` are unaffected and safe to use
+as-is.