migrate((db) => {
    const dao = new Dao(db);
    const collection = dao.findCollectionByNameOrId("time_entries");

    // Add is_banked field
    collection.schema.addField(new SchemaField({
        name: "is_banked",
        type: "bool",
        required: false, // Default true handled in app logic or ignored for now
        options: {}
    }));

    // Add manual_override field
    collection.schema.addField(new SchemaField({
        name: "manual_override",
        type: "bool",
        required: false,
        options: {}
    }));

    // Add calculated_hours field
    collection.schema.addField(new SchemaField({
        name: "calculated_hours",
        type: "number",
        required: false,
        options: {
            min: null,
            max: null,
            noDecimal: false
        }
    }));

    return dao.saveCollection(collection);
}, (db) => {
    const dao = new Dao(db);
    const collection = dao.findCollectionByNameOrId("time_entries");

    // logic to remove fields if needed, usually tricky in PB migrations securely without losing data
    // For now we just return null or attempt simple removal
    collection.schema.removeField("is_banked");
    collection.schema.removeField("manual_override");
    collection.schema.removeField("calculated_hours");

    return dao.saveCollection(collection);
})