CLPR: Middleware Layer

This issue is a roll-up issue for the development of the CLPR Middleware that acts as glue between:
* CLPR Messaging Layer
* CLPR Application Layer
* CLPR Connector Layer

In Hiero the CLPR Middleware will be implemented as native system contracts.

Reference solidity contracts will be provided for other EVM networks that interoperate over CLPR.

Once delivered, the middleware layer behavior is immutable.

No files, tests, or entry points are named. Start by mapping the CLPR Messaging, Application, and Connector Layers and defining how the native system contracts connect them in Hiero; reference Solidity contracts are intended for other interoperating EVM networks. Done means the middleware behavior is delivered and immutable.

Written by the indexing model from the issue text.