fix: logo 右半部分从 CODING 改为 CODE

去掉难以正确渲染的 N 和 G 字母，右半部分简化为 CODE（4 字母），
与左半部分 AIR 组合为 AIR CODE。

packages/opencode/test/config/fixtures/markdown-header.md

@@ -0,0 +1,11 @@
+# Response Formatting Requirements
+
+Always structure your responses using clear markdown formatting:
+
+- By default don't put information into tables for questions (but do put information into tables when creating or updating files)
+- Use headings (##, ###) to organise sections, always
+- Use bullet points or numbered lists for multiple items
+- Use code blocks with language tags for any code
+- Use **bold** for key terms and emphasis
+- Use tables when comparing options or listing structured data
+- Break long responses into logical sections with headings