Unify accept and network threads into io threads

design.md

@@ -19,7 +19,7 @@ WeaselDB is a high-performance write-side database component designed for system
 
 - **Ultra-fast arena allocation** (~1ns vs ~20-270ns for malloc)
 - **High-performance JSON parsing** with streaming support and SIMD optimization
-- **Multi-threaded networking** using epoll with thread pools
+- **Multi-threaded networking** using epoll with unified I/O thread pool
 - **Zero-copy design** throughout the pipeline
 - **Factory pattern safety** ensuring correct object lifecycle management
 
@@ -90,13 +90,13 @@ Ultra-fast memory allocator optimized for request/response patterns:
 #### **Networking Layer**
 
 **Server** (`src/server.{hpp,cpp}`):
-- **High-performance multi-threaded networking** using epoll with thread pools
+- **High-performance multi-threaded networking** using epoll with unified I/O thread pool
 - **Factory pattern construction** via `Server::create()` ensures proper shared_ptr semantics
 - **Safe shutdown mechanism** with async-signal-safe shutdown() method
 - **Connection ownership management** with automatic cleanup on server destruction
 - **Pluggable protocol handlers** via ConnectionHandler interface
-- **Multi-threaded architecture:** separate accept and network thread pools
-- **EPOLL_EXCLUSIVE** load balancing across accept threads
+- **Unified I/O architecture:** single thread pool handles both connection acceptance and I/O processing
+- **EPOLL_EXCLUSIVE** on listen socket prevents thundering herd across I/O threads
 
 **Connection** (`src/connection.{hpp,cpp}`):
 - **Efficient per-connection state management** with arena-based memory allocation