docs(readme): clarify EverOS positioning (#262)

Rename the overview section to focus on why EverOS matters in both English and Chinese READMEs.

Simplify the EverMind ecosystem copy around EverOS as the core memory architecture and mirror that positioning in the Chinese README.

README.md

@@ -22,7 +22,7 @@
 <br>
 
 - [EverOS 1.0.0 Highlights](#everos-100-highlights)
-- [What Is EverOS](#what-is-everos)
+- [Why EverOS](#why-everos)
 - [Quick Start](#quick-start)
 - [Architecture At A Glance](#architecture-at-a-glance)
 - [Storage Layout](#storage-layout)
@@ -96,7 +96,7 @@ Search independently by <code>user_id</code>, <code>agent_id</code>,
 </div>
 
 
-## What Is EverOS
+## Why EverOS
 
 EverOS is an open-source Python framework for self-evolving long-term
 memory across agents and platforms. It gives makers one portable memory
@@ -675,7 +675,7 @@ Star the repo or join the community links above to follow new architecture metho
 
 ## EverMind Ecosystems
 
-EverMind is an open-source ecosystem for long-term memory, self-evolving agents, and memory evaluation. EverOS is the core runtime architecture; EverMemOS is the paper and research line carrying our strongest memory-system benchmark runs; EverAlgo supplies the next-generation algorithms that make the system modular and reusable.
+EverMind is an open-source ecosystem for long-term memory, self-evolving agents, and memory evaluation.
 
 <table>
 <tr>
@@ -683,7 +683,7 @@ EverMind is an open-source ecosystem for long-term memory, self-evolving agents,
 </tr>
 <tr>
 <td><strong>Core Memory Architecture</strong></td>
-<td><a href="https://github.com/EverMind-AI/EverOS">EverOS</a> / EverMemOS - the local memory operating system and research-backed runtime for agent and user memory.</td>
+<td><a href="https://github.com/EverMind-AI/EverOS">EverOS</a> - the local memory operating system and research-backed runtime for agent and user memory.</td>
 </tr>
 <tr>
 <td><strong>Algorithm Engine</strong></td>