refactor: service card and opening times optimisation

[james-cross]

Summary

Extracts shared components and utilities from duplicated code across ServiceCard, GroupedServiceCard, and OrganisationServicesAccordion. Moves per-render work to data processing time where possible.

Part of the services API and rendering optimisation series (chunks 02-04).

Changes

• Extract OpeningTimesList component and formatOpeningTimes utility from duplicated opening times IIFEs in ServiceCard and OrganisationServicesAccordion
• Extract VerifiedBadge component from duplicated inline SVG in ServiceCard and GroupedServiceCard
• Extract buildOrganisationUrl utility from duplicated URL construction in both card components
• Simplify opening times cache key to use service ID only (TTL check already handles expiry individually, minute-based key caused batch invalidation)
• Split ServiceCard useMemo into service-specific ([service]) and URL-specific ([slug, location, searchParams]) memos
• Move appointment-only keyword detection from isServiceOpenNow (per-render) to processServiceData (once per service)
• Pre-decode text (decodeText) in processServiceData instead of per-render in cards
• Skip LazyMarkdownContent for plain text descriptions (render <p> instead)
• Merge services count query into single $facet pipeline (previous commit)
• Centralise config constants, cache headers, and env vars (previous commit)

Testing

• All 463 passing unit tests continue to pass (3 flaky sitemap tests are pre-existing and environment-dependent)
• Updated openingTimes tests to reflect appointment-only detection architecture change
• TypeScript type check passes with no errors
• ESLint passes with no warnings
• Next.js production build succeeds
• New components (OpeningTimesList, VerifiedBadge) covered by existing ServiceCard and accordion tests