Fix/292 ssr claim receipt

[karanjakevin39-collab]

• Convert claim-receipt page from a client-fetched (useEffect + mock
  data) page to an async Server Component that fetches
  /api/v1/claims/{id}/receipt during SSR
• Mark the route force-dynamic and fetch with cache: 'no-store' so the
  backend's own Cache-Control header (private, must-revalidate, [HIGH] Hash all legacy plaintext API keys and drop plaintext column #32)
  governs revalidation instead of Next's data cache
• Extract the interactive Back button into its own client component
• Widen ClaimReceiptData status union to include 'cancelled', matching
  the backend DTO
• Add a mock handler for /api/v1/claims/:id/receipt so SSR works
  locally with NEXT_PUBLIC_USE_MOCKS=true
• Add Playwright + an E2E test asserting FCP < 1s under a throttled
  Slow 3G / 4x CPU profile

Closes #292

[kilodesodiq-arch]

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[karanjakevin39-collab]

please merge fixed the failing checks

[kilodesodiq-arch]

LGTM