feat(react): Add support for React 19 (#763)

Supports both React 18 & 19 as possible peer dependencies in the
`@anywidget/react` module. The starter template now defaults to React
19.

.changeset/wise-poets-look.md

@@ -0,0 +1,5 @@
+---
+"@anywidget/react": minor
+---
+
+Support React 19

packages/create-anywidget/__tests__/__snapshots__/index.test.js.snap

@@ -112,8 +112,8 @@ src/ipyfoo/static
 	},
 	"dependencies": {
 		"@anywidget/react": "0.0.8",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1"
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0"
 	},
 	"devDependencies": {}
 }",
@@ -341,12 +341,12 @@ src/ipyfoo/static
 	},
 	"dependencies": {
 		"@anywidget/react": "0.0.8",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1"
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0"
 	},
 	"devDependencies": {
-		"@types/react": "^18.3.12",
-		"@types/react-dom": "^18.3.1",
+		"@types/react": "^19.0.1",
+		"@types/react-dom": "^19.0.2",
 		"typescript": "^5.7.2"
 	}
 }",
@@ -1304,8 +1304,8 @@ src/ipyfoo/static
 	},
 	"dependencies": {
 		"@anywidget/react": "0.0.8",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1"
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0"
 	},
 	"devDependencies": {
 		"esbuild": "^0.24.0"
@@ -1535,12 +1535,12 @@ src/ipyfoo/static
 	},
 	"dependencies": {
 		"@anywidget/react": "0.0.8",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1"
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0"
 	},
 	"devDependencies": {
-		"@types/react": "^18.3.12",
-		"@types/react-dom": "^18.3.1",
+		"@types/react": "^19.0.1",
+		"@types/react-dom": "^19.0.2",
 		"typescript": "^5.7.2",
 		"esbuild": "^0.24.0"
 	}

packages/create-anywidget/package.json

@@ -28,11 +28,11 @@
 		"@anywidget/react": "workspace:^",
 		"@anywidget/types": "workspace:^",
 		"@types/node": "^22.10.1",
-		"@types/react": "^18.3.12",
-		"@types/react-dom": "^18.3.1",
+		"@types/react": "^19.0.1",
+		"@types/react-dom": "^19.0.2",
 		"esbuild": "^0.24.0",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1",
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0",
 		"typescript": "^5.7.2"
 	}
 }

packages/react/package.json

@@ -15,16 +15,16 @@
 		}
 	},
 	"peerDependencies": {
-		"@types/react": "^18.0.0",
-		"@types/react-dom": "^18.0.0",
-		"react": "^18.0.0",
-		"react-dom": "^18.0.0"
+		"@types/react": "^18.0.0 || ^19.0.0",
+		"@types/react-dom": "^18.0.0 || ^19.0.0",
+		"react": "^18.0.0 || ^19.0.0",
+		"react-dom": "^18.0.0 || ^19.0.0"
 	},
 	"devDependencies": {
-		"@types/react": "^18.3.12",
-		"@types/react-dom": "^18.3.1",
-		"react": "^18.3.1",
-		"react-dom": "^18.3.1"
+		"@types/react": "^19.0.1",
+		"@types/react-dom": "^19.0.2",
+		"react": "^19.0.0",
+		"react-dom": "^19.0.0"
 	},
 	"dependencies": {
 		"@anywidget/types": "workspace:^"