feat: add custom words autocomplete support for Prompt node

Adds custom words autocomplete functionality similar to comfyui-custom-scripts,
with the following features:

Backend (Python):
- Create CustomWordsService for CSV parsing and priority-based search
- Add API endpoints: GET/POST /api/lm/custom-words and
  GET /api/lm/custom-words/search
- Share storage with pysssss plugin (checks for their user/autocomplete.txt first)
- Fallback to Lora Manager's user directory for storage

Frontend (JavaScript/Vue):
- Add 'custom_words' and 'prompt' model types to autocomplete system
- Prompt node now supports dual-mode autocomplete:
  * Type 'emb:' prefix → search embeddings
  * Type normally → search custom words (no prefix required)
- Add AUTOCOMPLETE_TEXT_PROMPT widget type
- Update Vue component and composable types

Key Features:
- CSV format: word[,priority] compatible with danbooru-tags.txt
- Priority-based sorting: 20% top priority + prefix + include matches
- Preview tooltip for embeddings (not for custom words)
- Dynamic endpoint switching based on prefix detection

Breaking Changes:
- Prompt (LoraManager) node widget type changed from
  AUTOCOMPLETE_TEXT_EMBEDDINGS to AUTOCOMPLETE_TEXT_PROMPT
- Removed standalone web/comfyui/prompt.js (integrated into main widgets)

Fixes comfy_dir path calculation by prioritizing folder_paths.base_path
from ComfyUI when available, with fallback to computed path.

vue-widgets/src/composables/useAutocomplete.ts

@@ -3,7 +3,7 @@ import { ref, onMounted, onUnmounted, type Ref } from 'vue'
 // Dynamic import type for AutoComplete class
 type AutoCompleteClass = new (
   inputElement: HTMLTextAreaElement,
-  modelType: 'loras' | 'embeddings',
+  modelType: 'loras' | 'embeddings' | 'custom_words' | 'prompt',
   options?: AutocompleteOptions
 ) => AutoCompleteInstance
 
@@ -29,7 +29,7 @@ export interface UseAutocompleteOptions {
 
 export function useAutocomplete(
   textareaRef: Ref<HTMLTextAreaElement | null>,
-  modelType: 'loras' | 'embeddings' = 'loras',
+  modelType: 'loras' | 'embeddings' | 'custom_words' | 'prompt' = 'loras',
   options: UseAutocompleteOptions = {}
 ) {
   const autocompleteInstance = ref<AutoCompleteInstance | null>(null)