feat(ep-commerce): catalog-search enhancements for faceted search pages

[field123]

Closes #351. (Supersedes #352, which GitHub auto-closed when its head branch was renamed to drop a project-specific prefix.)

Reusable additions to the EP catalog-search components for building faceted, deep-linked search result pages. All handlers ride the $ctx data context so Plasmic designers wire interactions without component refs.

Changes

Component	Addition
EPCatalogSearchProvider	baseFilter prop — injected via InstantSearch <Configure filters> so it persists across facet refinement (adapter-level filter_by does not). highlightFullFields prop → Typesense highlight_full_fields.
EPSearchHits	Exposes resolved extensions and rawData on currentProduct so the PDP field components work inside hit cards unchanged. Configurable productPathPrefix for the hit link. Recovers EP's bare-keyed highlights from the raw Typesense hit and exposes _snippetedDescription.
EPRefinementList	singleSelect (radio-style via useMenu, count-desc ordering) + itemGap for the pill row. The design-time canvas mock mirrors the singleSelect flex pill-row so the visual builder matches runtime.
EPClearRefinements	alwaysRender for always-visible "all"-style affordances (style off clearRefinementsData.canRefine).
EPSearchPagination	goTo / next / prev exposed on searchPaginationData.
EPSearchAutocomplete	clear / setQuery exposed on autocompleteData.

Why the base filter goes through <Configure filters>

The adapter joins Configure's filters with generated facet filters (&&), but drops additionalSearchParameters.filter_by as soon as InstantSearch generates its own filters (i.e. on any facet refinement). Routing the base filter through filters is the only way it survives a facet selection — verified live (selecting a scope facet no longer re-admits filtered-out documents, e.g. variation children).

Testing

• All package tests pass (catalog-search-components.test.tsx extended: base-filter/highlight provider config, hit extensions + rawData + productPathPrefix + highlight recovery, singleSelect menu semantics + canvas mock layout).
• Verified end-to-end against a live storefront search page (Playwright, 1440px + 390px): live search-as-you-type + URL sync + back/forward, autocomplete, single-select scope facet with live counts + clear-all, query-term highlighting in title and snippet, numbered pagination with page indicator, reference links to the PDP, empty state, header-search hand-off.

Notes

• No production build artifacts are committed (source only).
• Single commit on master.