feat: implement inline autocomplete suggestions with FastAPI backend and Milkdown editor integration

src/components/GhostTextOverlay.vue

@@ -0,0 +1,47 @@
+<template>
+  <div v-if="visible" class="ghost-text-overlay" :style="overlayStyle"
+       @click="acceptSuggestion"
+  >{{ suggestion }}
+  </div>
+</template>
+
+<script setup>
+import { computed } from 'vue'
+
+const props = defineProps({
+    suggestion: { type: String, default: '' },
+    position: { type: Object, required: true },
+})
+
+const emit = defineEmits(['accept', 'dismiss'])
+
+const visible = computed(() => props.suggestion && props.position)
+
+const overlayStyle = computed(() => ({
+    position: 'absolute',
+    left: `${props.position.left}px`,
+    top: `${props.position.top}px`,
+    fontSize: `${props.position.fontSize || 16}px`,
+    fontFamily: props.position.fontFamily || 'monospace',
+    color: '#999',
+    backgroundColor: 'transparent',
+    pointerEvents: 'auto',
+    cursor: 'text',
+    whiteSpace: 'pre-wrap',
+    zIndex: 1000,
+}))
+
+const acceptSuggestion = () => emit('accept')
+</script>
+
+<style scoped>
+.ghost-text-overlay {
+    opacity: 0.6;
+    user-select: none;
+}
+
+.ghost-text-overlay:hover {
+    opacity: 1;
+    color: #666;
+}
+</style>