style(代码配色): 全站代码换成 Dracula 配色（亮色用官方浅色版 Alucard）；编辑器、题面和教程的代码块、练一练、提交详情的颜色一模一样了

原来三套配色各管一块：编辑器是 smoothy / One Dark，正文代码块和练一练是仿 GitHub，
提交详情是 Naive 自带的，同一段 printf 在一课里就有两种颜色。现在静态代码也走编辑器
那套 lezer 解析器，颜色只在 shared/highlight.css 写一份，highlight.js 删掉。

填空题顺手修好：空会把语法搅乱，(humidity ____ 40) 被认成类型声明、humidity 染成类型色，
现在空里先填上答案再解析，答案不输出。

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/shared/components/CodeEditor.vue

@@ -7,8 +7,7 @@ import CodeMirror from "./CodeMirror.vue"
 import type { Extension } from "@codemirror/state"
 import { autocompletion, closeBrackets, completeAnyWord } from "@codemirror/autocomplete"
 import type { LANGUAGE } from "utils/types"
-import { oneDark } from "../themes/oneDark"
-import { smoothy } from "../themes/smoothy"
+import { darkCodeTheme, lightCodeTheme } from "../themes/codeTheme"
 import { styleTheme } from "shared/extensions/baseTheme"
 import { enhanceCompletion } from "shared/extensions/autocompletion"
 
@@ -47,7 +46,7 @@ const extensions = computed(() => [
   autocompletion({
     override: [enhanceCompletion(language), completeAnyWord],
   }),
-  isDark.value ? oneDark : smoothy,
+  isDark.value ? darkCodeTheme : lightCodeTheme,
   ...extraExtensions,
 ])
 </script>

apps/web/src/shared/components/Markdown.vue

@@ -1,7 +1,6 @@
 <script setup lang="ts">
 import { useThemeVars } from "naive-ui"
 import { renderMarkdown } from "shared/markdown"
-import "shared/highlight.css"
 
 /**
  * 显示一段 Markdown / HTML 正文：题面、教程、AI 的提示和报告。

apps/web/src/shared/components/MarkdownEditor.vue

@@ -6,8 +6,7 @@ import { Icon } from "@iconify/vue"
 import CodeMirror from "./CodeMirror.vue"
 import { uploadImage } from "../../admin/api"
 import { styleTheme } from "../extensions/baseTheme"
-import { oneDark } from "../themes/oneDark"
-import { smoothy } from "../themes/smoothy"
+import { darkCodeTheme, lightCodeTheme } from "../themes/codeTheme"
 
 /**
  * 后台教程正文的 Markdown 编辑器：左边写，右边由教程编辑页用学生端同一套组件预览。
@@ -145,7 +144,7 @@ const extensions = computed(() => [
   EditorView.lineWrapping,
   imageEvents,
   shortcuts,
-  isDark.value ? oneDark : smoothy,
+  isDark.value ? darkCodeTheme : lightCodeTheme,
 ])
 
 const tools = computed(() => [

apps/web/src/shared/components/SyncCodeEditor.vue

@@ -5,8 +5,7 @@ import { autocompletion, closeBrackets, completeAnyWord } from "@codemirror/auto
 import type { EditorView } from "@codemirror/view"
 import type { Extension } from "@codemirror/state"
 import type { LANGUAGE } from "utils/types"
-import { oneDark } from "../themes/oneDark"
-import { smoothy } from "../themes/smoothy"
+import { darkCodeTheme, lightCodeTheme } from "../themes/codeTheme"
 import { styleTheme } from "shared/extensions/baseTheme"
 import { enhanceCompletion } from "shared/extensions/autocompletion"
 import { languageExtension } from "shared/extensions/language"
@@ -60,7 +59,7 @@ const extensions = computed(() => [
   langExtension.value,
   bracketMatching(),
   closeBrackets(),
-  isDark.value ? oneDark : smoothy,
+  isDark.value ? darkCodeTheme : lightCodeTheme,
   autocompletion({
     override: [enhanceCompletion(language), completeAnyWord],
   }),