Add retry, staleTime, and refetchOnWindowFocus query options

[KidkArolis]

New query configuration options for resilience and freshness control:

• retry: Automatic retry with exponential backoff on fetch failures
  (default: 3 retries, 1s→2s→4s... capped at 30s)
• retryDelay: Custom delay function or fixed ms between retries
• staleTime: Time data is considered "fresh" before background refetch
  (default: 30s - prevents refetch storms from rapid tab switching)
• refetchOnWindowFocus: Refetch stale queries when window regains focus
  (default: true - catches missed realtime events after dormancy)

All options work as global defaults via Figbird constructor:

new Figbird({
  adapter,
  defaultQueryConfig: {
    retry: 3,
    staleTime: 60_000,
    refetchOnWindowFocus: true,
  }
})

Or as per-query overrides:

useFind('messages', { staleTime: 0, retry: false })

The 30s default staleTime balances two concerns:

• Realtime events keep data fresh in normal operation
• Refetch catches edge cases (laptop sleep, background tab throttling)
• Rapid tab switching won't cause refetch storms