Refactor imports and types for consistency and remove redundant paths

- Updated relative imports by replacing `@/` aliases with proper `../` paths for consistency.
- Refined type definitions in IPC handlers and repositories (`User`, `Chapter`, `Act`, etc.).
- Simplified return types in `Location` model methods for streamlined usage.

electron/database/repositories/plotpoint.repository.ts

@@ -1,5 +1,5 @@
 import { Database, QueryResult, RunResult, SQLiteValue } from "node-sqlite3-wasm";
-import System from "@/electron/database/System";
+import System from "../System.js";
 
 export interface BookPlotPointsTable extends Record<string, SQLiteValue> {
     plot_point_id: string;