CLPR-2.1: Messaging wire formats, state schema, and system contract interface

## Story CLPR-2.1: Messaging Wire Formats, State Schema, and System Contract Interface

**Parent Epic:** CLPR-2: Messaging Layer
**Repo:** hiero-ledger/hiero-consensus-node

### Objective

Define protobuf wire formats, state stores, and the CLPR system contract interface for the messaging layer. Downstream stories compile against these types.

### Acceptance Criteria

- **AC-1:** HAPI transaction bodies defined: `ClprSubmitBundleTransactionBody` (connection_id, proof_bytes, remote_endpoint_signature), `ClprRedactMessageTransactionBody` (connection_id, message_id). Note: `sendMessage` is NOT a HAPI transaction — it is a system contract method.
- **AC-2:** CLPR system contract Solidity interface includes `sendMessage(bytes32 connectionId, bytes connectorId, bytes targetApplication, bytes messageData) returns (uint64 messageId)`. This is callable by application smart contracts.
- **AC-3:** `ClprMessagePayload` oneof with three variants: `ClprMessage` (data), `ClprMessageReply` (response), `ClprControlMessage` (control).
- **AC-4:** `ClprMessage`: `connector_id`, `target_application`, `sender`, `message_data`.
- **AC-5:** `ClprMessageReply`: `message_id` (uint64), `status` (enum: SUCCESS=0, APPLICATION_ERROR=1, CONNECTOR_NOT_FOUND=2, CONNECTOR_UNDERFUNDED=3, REDACTED=5), `message_reply_data` (bytes).
- **AC-6:** `ClprMessageKey`: `(connection_id, message_id)`. `ClprMessageValue`: `payload` + `running_hash_after_processing`.
- **AC-7:** `ClprQueueMetadata`: `next_message_id`, `sent_running_hash`, `received_message_id`, `received_running_hash`.
- **AC-8:** State stores: `MESSAGE_QUEUE` K/V (ClprMessageKey → ClprMessageValue), `MESSAGE_QUEUE_METADATA` K/V (connection_id → queue metadata).
- **AC-9:** `TransactionBody` oneof extended with `ClprSubmitBundle` and `ClprRedactMessage`.
- **AC-10:** Transaction records: `ClprSubmitBundle` includes message count, generated response IDs, slash events.
- **AC-11:** All MATS pass.

### Notes

- `ClprControlMessage` must be added to the `ClprMessagePayload` oneof (missing from prototype per Finding F-1).
- `ClprMessage` needs `connector_id`, `target_application`, `sender` fields (missing from prototype per Finding F-2).
- `ClprMessageReplyStatus` enum needs to be added (missing from prototype per Finding F-3).
- The `sendMessage` return value (`messageId`) is available to the calling smart contract for correlation with the eventual response.

### Dependencies

- CLPR-1.1 (extends network-layer types)

### Risk

**Medium** — Introduces the CLPR system contract pattern. The system contract must be callable from EVM context and interact with native CLPR service state.

Read the CLPR-1.1 network-layer types and the existing CLPR prototype first; map the protobuf transaction, payload, key/value, metadata, and record definitions plus the Solidity system-contract interface. Use the acceptance criteria as the completion checklist and run MATS.

Written by the indexing model from the issue text.