feat: add erc20 multi-minter support

[kpitapeersyst]

feat: add erc20 multi-minter support

Replaces the single-owner model for ERC20 token pairs with a multi-minter authorization model. Each TokenPair now stores an owner_addresses list, and mint/burn authorization checks any address in that list instead of a single owner.

Key changes

• Proto / types: TokenPair.owner_address is deprecated in favor of owner_addresses (repeated string). MsgTransferOwnership is replaced by MsgAddMinter and MsgRemoveMinter. Query OwnerAddress is replaced by OwnerAddresses (now accepting a denom argument). Queries still populate the deprecated owner_address field for backwards compatibility.
• Keeper: single-owner mint authorization is replaced by IsAuthorizedMinter. MigrateOwnerAddresses migrates existing token pairs from the single-owner field to the list. Dedicated multi_minter.go holds the minter management logic, transfer_ownership.go is removed.
• Precompiles: Owner() and TransferOwnership() are removed from the ERC20/WERC20 precompiles (IOwnable.sol, ABI, events, interface, types). Burn0 uses the new multi-minter check.
• Validation: MsgAddMinter / MsgRemoveMinter ValidateBasic accepts the configured bech32 address prefix; owner-addresses list length check is removed from TokenPair.Validate, IBC empty-owner case documented.
• Tests: new coverage for AddMinter/RemoveMinter (msg server + e2e), multi-minter keeper paths, MintCoins, GetTokenPair(s) owner fields, migration (legacy owner can still mint), query OwnerAddresses by denom, IsAuthorizedMinter, HasDuplicates, and ValidateOwnerAddresses. Removes obsolete precompile ownership/transfer-ownership tests.
• Misc fixes: regenerate werc20/abi.json, add HasDuplicates helper in utils.

Files most worth reviewing

• proto/cosmos/evm/erc20/v1/{erc20,tx,query}.proto
• x/erc20/keeper/multi_minter.go, x/erc20/keeper/msg_server.go, x/erc20/keeper/mint.go
• x/erc20/types/{msg.go,token_pair.go,errors.go}
• precompiles/erc20/{erc20.go,tx.go,events.go,types.go,interfaces.go,query.go}
• precompiles/erc20/IOwnable.sol (removal) and precompiles/{erc20,werc20}/abi.json

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• tackled an existing issue or discussed with a team member
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• targeted the release/v0.6.x-xrplevm branch