Update GraphPanel.vue and WorkbenchPanel.vue for improved UI and clarity

- Changed maximize button icon for better visual representation.
- Revised descriptions in WorkbenchPanel.vue to enhance clarity and context regarding ontology generation and graph building processes.
- Updated step titles and descriptions to reflect more accurate terminology and user guidance.

frontend/src/components/GraphPanel.vue

@@ -9,7 +9,7 @@
           <span class="btn-text">Refresh</span>
         </button>
         <button class="tool-btn" @click="$emit('toggle-maximize')" title="最大化/还原">
-          <span class="icon-maximize">×</span>
+          <span class="icon-maximize">⛶</span>
         </button>
       </div>
     </div>