feat(query-core, query-devtools): show how query handles started their queries

.changeset/experimental-query-handles.md

@@ -0,0 +1,6 @@
+---
+'@tanstack/query-core': minor
+'@tanstack/react-query': minor
+---
+
+Add experimental query handles. `experimental_queryHandle`, `experimental_queryHandleAsync` and `experimental_ensureQueryHandle` start a query from a query factory and return a small serializable handle: the first doesn't wait, the second waits for fresh data, and the third waits for any data, even if it is stale. `experimental_fromHandle` rebuilds the query's options from a handle. `experimental_getQueryHandleData` reads the data of a handle that one of the awaited functions returned. `experimental_InferQueryHandleData` gives the type of the data a reader gets from a factory or handle.

.changeset/query-handles-devtools.md

@@ -0,0 +1,6 @@
+---
+'@tanstack/query-core': minor
+'@tanstack/query-devtools': minor
+---
+
+Show in the devtools how experimental query handles started their queries. In development, `experimental_getQueryStartInfo` returns which handle function started a query, where and when, and whether anything has read it since. Production builds record nothing. The devtools show this, mark with a `waterfall` badge queries whose first fetch a component's query hook started on a client that uses handles, and flag prefetched queries that nothing read. In development, `dehydrate` warns when it leaves out a pending query that a handle function started on the server.

docs/config.json

@@ -343,6 +343,10 @@
               "label": "Prefetching & Router Integration",
               "to": "framework/react/guides/prefetching"
             },
+            {
+              "label": "Query Handles (experimental)",
+              "to": "framework/react/guides/query-handles"
+            },
             {
               "label": "Server Rendering & Hydration",
               "to": "framework/react/guides/ssr"