fix(copywriting): 清理静态SVG与CSS中残留的AI生硬造词与测试口号，统一为自然工程描述

tests/generate_showcases.py

@@ -284,7 +284,7 @@ service_agent_svg = '''<svg width="600" height="380" viewBox="0 0 600 380" fill=
   <circle cx="64" cy="37" r="4.5" fill="#10B981"/>
   <text x="84" y="41" fill="#475569" font-family="'Inter', sans-serif" font-size="12" font-weight="600">Enterprise Private AI Agent &amp; RAG Architecture · 企业私域智能体与知识库</text>
   <rect x="500" y="27" width="66" height="20" rx="2" fill="#FAF5FF" stroke="#7C3AED" stroke-width="1"/>
-  <text x="506" y="41" fill="#7C3AED" font-family="'Noto Serif SC', 'SimSun', serif" font-size="11" font-weight="700">格物致知</text>
+  <text x="506" y="41" fill="#7C3AED" font-family="'Noto Serif SC', 'SimSun', serif" font-size="11" font-weight="700">私域智能</text>
 
   <!-- 左侧：企业私域多源知识库接入 -->
   <g transform="translate(30, 80)">