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/MemoryPalaceActionDemo.vue

@@ -9,7 +9,7 @@
 -->
 
 <script setup>
-import { ref, computed, nextTick } from 'vue'
+import { ref, computed } from 'vue'
 
 const scenarios = {
   coding: {
@@ -142,16 +142,6 @@ const prevStep = () => {
     currentStepIndex.value--
   }
 }
-
-// Visual helpers
-const getLayerStyle = (layerId) => {
-  const isActive = (layer) => {
-    // Logic to highlight active layer based on step action could go here
-    // For now, simple static colors
-    return true
-  }
-  return {}
-}
 </script>
 
 <template>