* add axum sse example
* fix: make the sse axum folder name correct
* feat: add common modules for Axum SSE example
This commit adds supporting modules for the Axum Server-Sent Events (SSE) example:
- Added `counter.rs` with a simple counter router implementation
- Added `jsonrpc_frame_codec.rs` for decoding JSON-RPC frames
- Created a `mod.rs` to expose these modules
- Removed the previous SSE example configuration from Cargo.toml
* move examples to root
* nit: remove extra newline here
