feat: enhance type organization and import structure

- Added detailed tasks in `TODO.md` for isolating and organizing types/interfaces across various services, including analytics, task management, and integrations.
- Updated imports in multiple files to use the new `@/services/core/database` path for consistency.
- Ensured all type imports are converted to `import type { ... }` where applicable for better clarity and performance.

src/services/analytics/analytics.ts

@@ -1,5 +1,5 @@
 import { Task, TaskStatus, TaskPriority, TaskSource } from '@/lib/types';
-import { prisma } from '../core/database';
+import { prisma } from '@/services/core/database';
 import { getToday, parseDate, subtractDays } from '@/lib/date-utils';
 
 export interface ProductivityMetrics {