refactor: add strict typing to core database methods in PlatformServiceMixin

- Replace all `any` types in $db, $exec, $one, $query, $first, and $contacts with proper interfaces:
  - Use QueryExecResult and DatabaseExecResult for raw database operations
  - Use Contact[] for contact queries
  - Add generics for mapped query results
- Update PlatformService and database interfaces to match new types
- Remove unused type imports and fix linter errors
- Reduces risk of runtime errors and improves type safety for all database access

src/services/PlatformService.ts

@@ -1,4 +1,4 @@
-import { QueryExecResult } from "@/interfaces/database";
+import { QueryExecResult, DatabaseExecResult } from "@/interfaces/database";
 
 /**
  * Represents the result of an image capture or selection operation.
@@ -145,10 +145,7 @@ export interface PlatformService {
    * @param params - The parameters to pass to the statement
    * @returns Promise resolving to the result of the statement
    */
-  dbExec(
-    sql: string,
-    params?: unknown[],
-  ): Promise<{ changes: number; lastId?: number }>;
+  dbExec(sql: string, params?: unknown[]): Promise<DatabaseExecResult>;
 
   /**
    * Executes a SQL query and returns the first row as an array.