docs: ♻️ Removed usage of null author, mandate usage of null for unset fields

app/changelog/page.mdx

@@ -18,6 +18,8 @@ This page lists changes since Working Draft 3. {{ className: 'lead' }}
     - Every field that used to be a URI now uses that entity's `id` field.
     - New endpoints have been defined under `/.versia/v0.6/` to fetch entities by their `id`.
 - Added [References](/types#reference) as a way to refer to other entities.
+- Mandated the usage of `null` for optional fields that are not set, instead of omitting them.
+- Changed usage of "`null` authors" to simply being an optional field.
 
 ## Since WD 4
 

app/entities/delete/page.mdx

@@ -24,8 +24,8 @@ Having the authorization is defined as:
 <Row>
     <Col>
         <Properties name="Delete">
-            <Property name="author" type="Reference | null" required={true} typeLink="/types#reference">
-                [Reference](/types#reference) to the `User` who is deleting the entity. [Can be set to `null` to represent the instance](/entities/instance-metadata#the-null-author).
+            <Property name="author" type="Reference" required={true} typeLink="/types#reference">
+                [Reference](/types#reference) to the `User` who is deleting the entity.
             </Property>
             <Property name="deleted_type" type="string" required={true}>
                 Type of the entity being deleted.

app/entities/instance-metadata/page.mdx

@@ -7,12 +7,6 @@ export const metadata = {
 
 Contains metadata about a Versia instance, such as capabilities and endpoints. {{ className: 'lead' }}
 
-## The `null` Author
-
-On some entities that have an `author` field, the `author` can be `null` to represent the instance itself as the author (like ActivityPub's Server Actors).
-
-Check the entity's documentation page to see if it supports this (it will be noted in the `author` field).
-
 ## Entity Definition
 
 <Row>

app/entities/page.mdx

@@ -12,7 +12,7 @@ Entities are the foundation of the Versia protocol. A similar concept to entitie
 
 An entity is a simple JSON object that represents a core data structure in Versia. Entities are used to represent various types of data, such as users, notes, and more. Each entity has a unique `id` property that is used to identify it within the instance.
 
-Any field in an entity not marked as `required` may be omitted or set to `null`.
+Any field in an entity not marked as `required` may be set to `null`. These fields **must not** be omitted: they must be present with a `null` value if not set.
 
 <Row>
   <Col>

app/structures/collection/page.mdx

@@ -16,8 +16,8 @@ Collections are a way to represent paginated groups of entities. They are used e
 <Row>
     <Col>
         <Properties name="Collection">
-            <Property name="author" type="Reference | null" required={true} typeLink="/types#reference">
-                [Reference](/types#reference) to the author of the collection. Usually the user who owns the collection. [Can be set to `null` to represent the instance](/entities/instance-metadata#the-null-author).
+            <Property name="author" type="Reference" required={false} typeLink="/types#reference">
+                [Reference](/types#reference) to the author of the collection. Usually the user who "owns" the collection.
             </Property>
             <Property name="total" type="number" required={true} numberType="u64">
                 Total number of entities in the collection, across all pages.
@@ -64,8 +64,8 @@ URI Collections are identical to regular collections, but they contain only URIs
 <Row>
     <Col>
         <Properties name="URICollection">
-            <Property name="author" type="Reference | null" required={true} typeLink="/types#reference">
-                [Reference](/types#reference) to the author of the collection. Usually the user who owns the collection. [Can be set to `null` to represent the instance](/entities/instance-metadata#the-null-author).
+            <Property name="author" type="Reference" required={false} typeLink="/types#reference">
+                [Reference](/types#reference) to the author of the collection. Usually the user who owns the collection.
             </Property>
             <Property name="total" type="number" required={true} numberType="u64">
                 Total number of entities in the collection, across all pages.