🦞 改进：龙虾图标优化

变更:
- 使用 logo.png 作为龙虾身体
- 缩小身份图标到 0.6em
- 龙虾主体增大到 3em

code/frontend/src/components/LobsterRiver/index.js

@@ -130,7 +130,7 @@ function LobsterRiver({ agents, onRefresh, onAgentToRiver, onAgentFromRiver }) {
               onMouseLeave={() => setHoveredAgent(null)}
               title={agent.name}
             >
-              <span className="agent-emoji lobster-body">🦞</span>
+              <img src="https://xjp.datalibstar.com/flying-hero/lobster-monitor/raw/branch/main/logo.png" alt="lobster" className="lobster-body-image" />
               <span className="agent-emoji agent-badge">{agent.emoji}</span>
               {hoveredAgent === agent.id && (
                 <span className="agent-name-tooltip">{agent.name}</span>
@@ -269,11 +269,12 @@ function LobsterRiver({ agents, onRefresh, onAgentToRiver, onAgentFromRiver }) {
 
         .agent-emoji {
         .lobster-body {
-          font-size: 2.5em;
+          font-size: 3em;
           filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.3));
         }
 
         .agent-badge {
+          font-size: 0.6em;
           position: absolute;
           bottom: -5px;
           right: -5px;