feat(implementation): rename files for improved clarity and update section title for context navigation

Author: phodal

docs/ai-friendly/ai-friendly-codebase.mdx renamed to docs/ai-friendly/codebase.mdx

@@ -1,5 +1,5 @@
 ---
-title: 上下文导航
+title: 上下文导航与度量
 hide_table_of_contents: true
 hide_title: true
 ---

docs/ai-friendly/context-navigator.mdx

@@ -190,8 +190,8 @@ const sidebars = {
 	],
 	friendlySidebar: [
 		'ai-friendly/index',
-		'ai-friendly/ai-friendly-codebase',
-		'ai-friendly/ai-friendly-platform-engineering',
+		'codebase',
+		'platform-engineering',
 		{
 			type: 'category',
 			label: 'AI-Friendly Question',