[blog + docs] React Labs: View Transitions, Activity, and more (#7772)

* init

* Add new error

* Bunch of updates

* Add addTransitionType

* Add Activity

* Expand on Activity

* Expand more on Activity

* Start on vt examples

* wip

* wip

* wip 2

* bump deploy

* wip

* wip

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* wip

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* wip

* wip

* init

* Add new error

* Bunch of updates

* Add addTransitionType

* Add Activity

* Expand on Activity

* Expand more on Activity

* Start on vt examples

* wip

* wip

* wip 2

* bump deploy

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* Update existing VT examples to use video items

* Suspense animation example

* Add customization example

* typos

* Remove TODOs -- we might still want these but cutting scope

* Address wp feedback

* Fix reorder example

* wip

* wip

* wip

* wip

* fix activity iframe resize

---------

Co-authored-by: Jack Pope <jackpope1@gmail.com>

src/sidebarBlog.json

@@ -11,6 +11,13 @@
       "path": "/blog",
       "skipBreadcrumb": true,
       "routes": [
+        {
+          "title": "React Labs: View Transitions, Activity, and more",
+          "titleForHomepage": "View Transitions and Activity",
+          "icon": "blog",
+          "date": "April 23, 2025",
+          "path": "/blog/2025/04/23/react-labs-view-transitions-activity-and-more"
+        },
         {
           "title": "React Compiler RC",
           "titleForHomepage": "React Compiler RC",