feat(mcp): refactor logging to use exchange for targeted client notifications (#132)

Refactors the MCP logging system to use the exchange mechanism for sending
logging notifications only to specific client sessions rather than broadcasting to all clients.

- Move logging notification delivery from server-wide broadcast to per-session exchange
- Implement per-session minimum logging level tracking and filtering
- Add proper logging level filtering at the exchange level
- Change setLoggingLevel from notification to request/response pattern (breaking change)
- Deprecate global server.loggingNotification in favor of exchange.loggingNotification
- Add SetLevelRequest record to McpSchema
- Add integration test demonstrating filtered logging notifications

Resolves #131

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>
Co-authored-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>