fix: TrustGateHook — selector mismatch, caller auth, admin events

[JhiNResH]

Fixes the blocking issues raised in review of PR #9.

Changes

CRITICAL fix — FUND_SEL selector

The original hook computed keccak256("fund(uint256,bytes)") but AgenticCommerce.fund is fund(uint256,uint256,bytes). The selector never matched, so client trust was never checked at the fund stage.

Fix: Inherit BaseERC8183Hook instead of raw IACPHook. This gives correct selector constants for free (they live in BaseERC8183Hook and match AgenticCommerce). The hook now overrides _preFund/_preSubmit/_postComplete/_postReject virtual functions — no manual selector dispatch needed.

HIGH fix — caller authentication

BaseERC8183Hook provides the onlyERC8183(jobId) modifier, which validates that msg.sender is the ERC-8183 core or the job's registered hook. Inheriting it adds this guard automatically. No extra code required.

MEDIUM fixes

• agentId == 0 collision — added mapping(address => bool) public registered to track existence separately from the agentId value. Wallets with agentId = 0 can now be registered correctly.
• Admin events — setAgentId, setAgentIds, setThreshold, and setOracle now emit AgentIdSet, ThresholdUpdated, and OracleUpdated respectively.
• Oracle zero-address guard — require(oracle_ != address(0)) in constructor and setOracle.

LOW fixes

• README: link now points to TrustGateHook.sol (was RNWYTrustGateHook.sol).

Constructor change (breaking)

The constructor gains a new first parameter:

// Before
constructor(address oracle_, uint8 threshold_, uint256 chainId_, string memory registry_)

// After
constructor(address erc8183Contract_, address oracle_, uint8 threshold_, uint256 chainId_, string memory registry_)

erc8183Contract_ is required by BaseERC8183Hook and stored as immutable. This is the AgenticCommerce core address (or MultiHookRouter address if used behind a router).