**Refactor directory scanning and add scan task support**

- Added a new `scan_directory` task to enable folder scans as asynchronous tasks while maintaining compatibility with the immediate backend.
- Introduced the `reconcile` function, replacing `generate_directory` for improved separation of concerns between database writes and read operations.
- Established a unique constraint on `Directory` (`one_directory_name_per_parent`) to prevent duplicate directories under the same parent.
- Added a "Scan" button to the frontend for re-reading folders from disk, along with new task invocation endpoints in the API.
- Updated tests across modules to validate the new `scan_directory` task, unique constraints, and database indexing logic.
- Improved cleanup logic for stale files, directories, and thumbnails to handle concurrent operations efficiently.
- Simplified `scan_comics` management command by removing user dependency and aligning it with the new `reconcile` function.
- Enhanced frontend components (`TheComicReader`, `TheComicList`, and others) to include lifecycle method cleanups, prevent memory leaks, and handle task-based scans.

frontend/src/main.js

@@ -15,8 +15,8 @@ import { library } from '@fortawesome/fontawesome-svg-core'
 import { FontAwesomeIcon } from '@fortawesome/vue-fontawesome'
 
 /* import specific icons */
-import {faBook, faBookOpen, faEdit, faTurnUp, faTimes, faCheck} from '@fortawesome/free-solid-svg-icons'
-library.add(faBook, faBookOpen, faEdit, faTurnUp, faTimes, faCheck)
+import {faBook, faBookOpen, faEdit, faTurnUp, faTimes, faCheck, faRefresh} from '@fortawesome/free-solid-svg-icons'
+library.add(faBook, faBookOpen, faEdit, faTurnUp, faTimes, faCheck, faRefresh)
 
 import router from './router'
 import store from './store'