Move the construction of the hybrid service stack, including all middleware and the RPC service, from the main `run` function into the `process_connection` function.
This change ensures that each incoming connection gets its own isolated service instance. This improves modularity by making the connection handling logic more self-contained and simplifies the main server loop.
Key changes:
- The `hybrid_service` and `rpc_service` are now created inside `process_connection`.
- The `run` function's responsibility is reduced to accepting TCP connections and spawning tasks for `process_connection`.