[doersf]

Fixes from a review against the SoChain API, before the first release:

• chart sends --currency only for price_usd; other series refuse it.
• Orphaned blocks (confirmations -1) parse and say they're orphaned.
• Inputs without an address are labelled by what they are: newly mined coins only for coinbase inputs, else the MWEB pool or "(no address)". Outputs into MWEB are labelled too.
• Litecoin blocks leave the carried-over MWEB pool out of "moved".
• price --time accepts unix seconds of 7 to 10 digits only, so milliseconds aren't silently answered with today's price.
• balance --time before a network's first block says so instead of looking like today's balance.
• Next-page hints keep --page-size and --currency.
• Transaction ids and block hashes are sent in lower case.
• A short 503 with Retry-After is waited out and retried.
• fees suggests the next block's median rounded up to a whole unit.
• rich-list --page is checked against the top 1,000.
• balance-history labels each period and says balances are at its end.
• Help and docs: keyless lookups are at least 2,500 a day; mcp install --use-api-key says where the key goes.