fix: resolve all ESLint errors in Vue components

Fixed 22 ESLint errors across 26 Vue component files:
- Removed TypeScript type annotations from ReadingProgress.vue (converted to JS)
- Removed unused variables, imports, and duplicate function declarations
- Fixed HTML parsing errors (invalid attribute names, unclosed tags)
- Added missing :key directives to v-for loops
- Fixed duplicate object keys (backgroundImage)
- Replaced special characters in comments to avoid parsing issues
- Fixed malformed HTML tags (v-else", 003e attributes)

All warnings were left unchanged as requested. Build now passes with 0 errors.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/.vitepress/theme/components/appendix/context-engineering/AgentContextFlow.vue

@@ -27,11 +27,9 @@ const currentCost = computed(() => (totalTokens.value / 1000 * costPer1kTokens).
 const systemHeight = computed(() => (systemPromptTokens / windowLimit) * 100)
 const inputHeight = computed(() => (currentInputTokens / windowLimit) * 100)
 // History 高度展示逻辑：
-// 我们希望展示“总高度”，即使超过 100%。
+// 我们希望展示"总高度"，即使超过 100%。
 // 父容器会限制显示区域，溢出部分通过视觉暗示。
 const historyHeight = computed(() => (historyTokens.value / windowLimit) * 100)
-
-const totalHeight = computed(() => systemHeight.value + historyHeight.value + inputHeight.value)
 </script>
 
 <template>