refactor: use id and foreignId methods in the CreateMediaTable migration

[artengin]

Refs: #68

[Copilot]

Pull Request Overview

This PR refactors the CreateMediaTable migration to use Laravel's newer id() and foreignId() methods instead of the older increments() and string() methods for primary and foreign key columns.

• Replace increments('id') with id() for the primary key
• Replace string('preview_id') with foreignId('preview_id') for the foreign key column

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[Copilot]

The foreignId('preview_id') method creates a BIGINT UNSIGNED column, while the original string('preview_id') created a VARCHAR column. This is a breaking change that could cause data type mismatches if existing data contains non-numeric preview IDs or if related tables expect string foreign keys.

Suggested change

	$table->foreignId('preview_id')->nullable();
	$table->string('preview_id')->nullable();