feat: add TIP-1034 TIP-20 channel reserve interface

[Lesnak1]

Summary

Adds the standard Solidity interface, precompile constants, and unit tests for the TIP-1034 TIP-20 Channel Reserve Precompile (0x4d50500000000000000000000000000000000000), introduced in Tempo Hardfork T5.

The TIP-20 Channel Reserve serves as the foundational on-chain primitive for the Machine Payments Protocol (MPP), locking payer deposits, settling increasing cumulative EIP-712 vouchers, and managing unilateral close grace timers.

Changes

1. src/interfaces/ITIP20ChannelReserve.sol:

   • Declares ChannelDescriptor, ChannelState, and Channel structs.
   • Declares all channel lifecycle methods: open, settle, topUp, close, requestClose, withdraw.
   • Declares getters: getChannel, getChannelState, getChannelStatesBatch, computeChannelId, getVoucherDigest, domainSeparator, storageCredits.
   • Declares events and custom errors.

2. src/StdPrecompiles.sol & src/Tempo.sol:

   • Added TIP20_CHANNEL_RESERVE_ADDRESS = 0x4d50500000000000000000000000000000000000.
   • Added typed TIP20_CHANNEL_RESERVE and Tempo.tip20ChannelReserve export.

3. test/TIP20ChannelReserve.t.sol:

   • Comprehensive test suite asserting precompile address exports, typed exports, 15 function selectors, and 13 custom error selectors against canonical hashes.

Verification

forge test
All tests passing across all suites.