feat: add CategoryImporter service and SeedCategoriesCommand for seeding category data

- Implemented CategoryImporter service to handle bulk export/import logic for categories.
- Created SeedCategoriesCommand to seed category tables from JSON files in data/seed/.
- Added validation and normalization for category data during import.
- Ensured proper error handling and user feedback during the seeding process.

graphify-out/cache/ast/v0.8.44/3a5610d926bb9581c868449c387e80feef104aec7c9bdc6ed39835e87c287015.json

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graphify-out/cache/ast/v0.8.44/4f34d9f9f45c9a445f12116cf0ee77b9105dfe11673bb77f0595861febc7851e.json

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graphify-out/cache/ast/v0.8.44/9bcf8a9b8f83e159a290b14c13b17b485185812c9e53ef62df4e33f84b216e47.json

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graphify-out/cache/ast/v0.8.44/c28e9c29f212ac946af73f8122b545bd3761766ebc2c8e0a47567ef6a9fc5197.json

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