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-search.md

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+# Product Search
+
+`Modules\Core\Search\ProductSearchService` provides locale-aware full-text product search on
+top of Laravel Scout + Meilisearch.
+
+---
+
+## Why locale-aware search isn't a filter
+
+Lunar's Meilisearch indexer (`Lunar\Search\ScoutIndexer::mapSearchableAttributes()`) flattens
+every translated attribute into **locale-suffixed fields on a single document** — a product with
+a translated `name` produces `name_en`, `name_el`, etc. as separate top-level fields, not
+separate documents per locale and not a filterable `locale` field.
+
+That means "search in Greek" isn't a `->filter('locale = el')` — Meilisearch has no such field to
+filter on. It's a choice of **which fields the query targets**: `name_el`/`description_el`
+instead of `name_en`/`description_en`. This is what Meilisearch's `attributesToSearchOn` search
+parameter controls, exposed through Scout via `Builder::options()`, which passes straight through
+to the underlying Meilisearch client call (`Laravel\Scout\Engines\MeilisearchEngine::performSearch()`
+merges `$builder->options` directly into the search request).
+
+---
+
+## Usage
+
+```php
+use Modules\Core\Search\ProductSearchService;
+
+$results = app(ProductSearchService::class)->search('running shoes');
+// or an explicit locale, bypassing App::getLocale():
+$results = app(ProductSearchService::class)->search('running shoes', 'el');
+```
+
+Returns an `Illuminate\Database\Eloquent\Collection` of `Lunar\Models\Product` — Scout's
+`->get()` hydrates real models from the database after the Meilisearch query, so relations
+(`variants`, `brand`, `media`, etc.) are available on the results as normal.
+
+`$locale` defaults to `App::getLocale()` — already set correctly on every storefront request by
+`Modules\Core\Localization\LocaleMiddleware` (see `localization.md`), so callers in controllers
+don't need to pass it explicitly.
+
+---
+
+## Missing-translation fallback
+
+If a product was only ever given an English name, `name_el` doesn't exist on that document at
+all (Lunar's indexer only writes a `{handle}_{locale}` field for locales actually present in the
+attribute's stored data — see `ScoutIndexer::mapSearchableAttributes()`). Searching strictly
+against `name_el` would make that product invisible to Greek-locale search, even though it's a
+real catalog item.
+
+To avoid silently hiding incompletely-translated products, `ProductSearchService` targets **both**
+the resolved locale's fields **and** the default language's fields
+(`Lunar\Models\Language::getDefault()->code`) — e.g. searching in `el` targets `name_el`,
+`name_en`, `description_el`, `description_en` together (assuming `en` is the default language).
+A product missing an `el` translation still matches via its `en` fields.
+
+---
+
+## Field list is dynamic, not hardcoded
+
+The set of attribute handles searched (`name`, `description`, or whatever else) comes from
+`Lunar\Facades\AttributeManifest::getSearchableAttributes(Product::morphName())` — the same
+source `ScoutIndexer` itself uses to decide what gets indexed. If an admin marks a new attribute
+searchable in the panel, `ProductSearchService` picks it up automatically; nothing in this class
+needs to change.
+
+---
+
+## Re-syncing after indexer changes
+
+Changing which attributes are searchable, or `ProductIndexer`'s filterable/sortable fields,
+requires re-syncing Meilisearch's index settings and re-indexing existing documents:
+
+```bash
+php artisan lunar:meilisearch:setup
+php artisan lunar:search:index "Lunar\Models\Product" --refresh
+```
+
+`ProductSearchService` itself needs no re-sync when locales change — `attributesToSearchOn` is
+computed per-query from the live language list, not baked into index settings.