Remove nodeKey field kind (#25847)

## Description

There has never been a way to use the nodeKey field kind since before
the simple simple-tree API layer was created. Any document using it is
impossible to open with our existing view schema APIs, and would have
had to have been created using either internal APIs or before
shared-tree was stabilized in FF 2.0.

## Breaking Changes

Removing support for nodeKey could cause a currently impossible to
"view" document which uses it from before FF 2.0 to error on load rather
than on view.

As such documents are believed to not exist, and if they do exist are
impossible to view or edit and never had forwards compat guarantees,
erroring on load for them seems like a non-issue.

Author: CraigMacomber

packages/dds/tree/src/feature-libraries/default-schema/defaultFieldKinds.ts

@@ -107,8 +107,7 @@ export const required = new FieldKindWithEditor(
 		// Which direction is allowed is a subjective policy choice.
 		(other.kind === sequence.identifier ||
 			other.kind === requiredIdentifier ||
-			other.kind === optional.identifier ||
-			other.kind === nodeKey.identifier) &&
+			other.kind === optional.identifier) &&
 		allowsTreeSchemaIdentifierSuperset(types, other.types),
 	new Set(),
 );
@@ -129,28 +128,6 @@ export const sequence = new FieldKindWithEditor(
 	new Set([]),
 );
 
-const nodeKeyIdentifier = "NodeKey";
-
-/**
- * Exactly one identifier.
- *
- * TODO: this is almost the same as identifier, but apparently unused.
- * Confirm if this is truly unused since before the document format was stabilized, and remove if possible.
- * @deprecated Superseded by {@link identifier}.
- */
-export const nodeKey = new FieldKindWithEditor(
-	nodeKeyIdentifier,
-	Multiplicity.Single,
-	noChangeHandler,
-	(types, other) =>
-		(other.kind === sequence.identifier ||
-			other.kind === requiredIdentifier ||
-			other.kind === optional.identifier ||
-			other.kind === nodeKeyIdentifier) &&
-		allowsTreeSchemaIdentifierSuperset(types, other.types),
-	new Set(),
-);
-
 const identifierFieldIdentifier = "Identifier";
 
 /**
@@ -214,7 +191,6 @@ export const fieldKindConfigurations: ReadonlyMap<
 	[
 		brand(1),
 		new Map<FieldKindIdentifier, FieldKindConfigurationEntry>([
-			[nodeKey.identifier, { kind: nodeKey, formatVersion: 1 }],
 			[required.identifier, { kind: required, formatVersion: 1 }],
 			[optional.identifier, { kind: optional, formatVersion: 1 }],
 			[sequence.identifier, { kind: sequence, formatVersion: 1 }],
@@ -225,7 +201,6 @@ export const fieldKindConfigurations: ReadonlyMap<
 	[
 		brand(2),
 		new Map<FieldKindIdentifier, FieldKindConfigurationEntry>([
-			[nodeKey.identifier, { kind: nodeKey, formatVersion: 1 }],
 			[required.identifier, { kind: required, formatVersion: 2 }],
 			[optional.identifier, { kind: optional, formatVersion: 2 }],
 			[sequence.identifier, { kind: sequence, formatVersion: 1 }],
@@ -236,7 +211,6 @@ export const fieldKindConfigurations: ReadonlyMap<
 	[
 		brand(3),
 		new Map<FieldKindIdentifier, FieldKindConfigurationEntry>([
-			[nodeKey.identifier, { kind: nodeKey, formatVersion: 1 }],
 			[required.identifier, { kind: required, formatVersion: 2 }],
 			[optional.identifier, { kind: optional, formatVersion: 2 }],
 			[sequence.identifier, { kind: sequence, formatVersion: 2 }],
@@ -247,7 +221,6 @@ export const fieldKindConfigurations: ReadonlyMap<
 	[
 		brand(4),
 		new Map<FieldKindIdentifier, FieldKindConfigurationEntry>([
-			[nodeKey.identifier, { kind: nodeKey, formatVersion: 1 }],
 			[required.identifier, { kind: required, formatVersion: 2 }],
 			[optional.identifier, { kind: optional, formatVersion: 2 }],
 			[sequence.identifier, { kind: sequence, formatVersion: 3 }],
@@ -284,7 +257,7 @@ export function getCodecTreeForModularChangeFormat(
  * code which uses this should be audited for compatibility considerations.
  */
 export const fieldKinds: ReadonlyMap<FieldKindIdentifier, FieldKindWithEditor> = new Map(
-	[required, optional, sequence, nodeKey, identifier, forbidden].map((s) => [s.identifier, s]),
+	[required, optional, sequence, identifier, forbidden].map((s) => [s.identifier, s]),
 );
 
 // Create named Aliases for nicer intellisense.

packages/dds/tree/src/test/snapshots/output/codec-tree/MinVersionForCollab.v2_0.json

@@ -26,10 +26,6 @@
               "name": "ModularChange",
               "version": 3,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2
@@ -78,10 +74,6 @@
               "name": "ModularChange",
               "version": 3,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2

packages/dds/tree/src/test/snapshots/output/codec-tree/MinVersionForCollab.v2_43.json

@@ -26,10 +26,6 @@
               "name": "ModularChange",
               "version": 4,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2
@@ -78,10 +74,6 @@
               "name": "ModularChange",
               "version": 4,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2

packages/dds/tree/src/test/snapshots/output/codec-tree/MinVersionForCollab.v2_52.json

@@ -26,10 +26,6 @@
               "name": "ModularChange",
               "version": 4,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2
@@ -78,10 +74,6 @@
               "name": "ModularChange",
               "version": 4,
               "children": [
-                {
-                  "name": "FieldKind:NodeKey",
-                  "version": 1
-                },
                 {
                   "name": "FieldKind:Value",
                   "version": 2