nft/v1 package

Package nft is the Launchpad collection ledger. Each collection is a GRC721 token whose transfer mode, royalties and metadata rules are fixed at creation. Collections are created, and their tokens minted, only by issuer realms: the Launchpad drops realm and any realm the config admin adds. Holders move, approve and burn their own tokens. The ledger has no admin of its own: nothing here can move a holder's token or change a collection's terms, and a paused lane stops only new collections and new mints.