Merkle Airdrop Claimer

Builds an OpenZeppelin-compatible tree — sorted pairs, odd nodes promoted — from a pasted or uploaded list, and shows the root. Finds your wallet in the list, generates its proof and verifies that proof against the root before offering to claim. Three leaf encodings are selectable, because a mismatch there is the most common reason a valid-looking claim reverts. The distributor address and claim signature are yours to supply; nothing is built in. If a claim reverts on the proof, the leaf encoding almost certainly does not match the contract, and switching the encoding option is the first thing to try before assuming the allocation list is wrong.