feat(nodes): add invocation classifications

Invocations now have a classification:
- Stable: LTS
- Beta: LTS planned, API may change
- Prototype: No LTS planned, API may change, may be removed entirely

The `@invocation` decorator has a new arg `classification`, and an enum `Classification` is added to `baseinvocation.py`.

The default is Stable; this is a non-breaking change.

The classification is presented in the node header as a hammer icon (Beta) or flask icon (prototype).

The icon has a tooltip briefly describing the classification.

invokeai/frontend/web/src/features/nodes/hooks/useNodeClassification.ts

@@ -0,0 +1,23 @@
+import { createMemoizedSelector } from 'app/store/createMemoizedSelector';
+import { stateSelector } from 'app/store/store';
+import { useAppSelector } from 'app/store/storeHooks';
+import { isInvocationNode } from 'features/nodes/types/invocation';
+import { useMemo } from 'react';
+
+export const useNodeClassification = (nodeId: string) => {
+  const selector = useMemo(
+    () =>
+      createMemoizedSelector(stateSelector, ({ nodes }) => {
+        const node = nodes.nodes.find((node) => node.id === nodeId);
+        if (!isInvocationNode(node)) {
+          return false;
+        }
+        const nodeTemplate = nodes.nodeTemplates[node?.data.type ?? ''];
+        return nodeTemplate?.classification;
+      }),
+    [nodeId]
+  );
+
+  const title = useAppSelector(selector);
+  return title;
+};