fix(widgets): reconcile widget store entry when widget type changes

registerWidget returned the existing store entry unconditionally, so when a
subgraph convert reused a graphId:nodeId:name key for a different widget, the
stale entry won and the widget rendered with the wrong type (a multiline text
widget showed as an int widget until a page reload rehydrated the store).

Keep the idempotent return only when the existing entry's type matches; on a
type mismatch the id now belongs to a different widget, so overwrite with the
live type and value. Same-type re-registration still preserves edited values.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: christian-byrne

src/stores/widgetValueStore.test.ts

@@ -112,6 +112,21 @@ describe('useWidgetValueStore', () => {
       expect(second.value).toBe(99)
     })
 
+    it('replaces a stale entry when the widget type changes', () => {
+      const store = useWidgetValueStore()
+      const first = store.registerWidget(seedA, state('number', 5))!
+      first.value = 42
+
+      // After a subgraph convert the graphId:nodeId:name key can be reused by a
+      // different widget. A type mismatch means it is not the same widget, so
+      // the live type/value must win rather than the stale entry (BUG: a text
+      // widget rendered as int until reload).
+      const reconciled = store.registerWidget(seedA, state('string', 'hello'))!
+      expect(reconciled.type).toBe('string')
+      expect(reconciled.value).toBe('hello')
+      expect(store.getWidget(seedA)?.type).toBe('string')
+    })
+
     it('registers a widget with all properties', () => {
       const store = useWidgetValueStore()
       const registered = store.registerWidget(

src/stores/widgetValueStore.ts

@@ -31,7 +31,9 @@ export const useWidgetValueStore = defineStore('widgetValue', () => {
     if (!isWidgetId(widgetId)) return undefined
 
     const existing = getWidget(widgetId)
-    if (existing) return existing as WidgetState<TValue>
+    if (existing && existing.type === init.type) {
+      return existing as WidgetState<TValue>
+    }
 
     const { graphId, nodeId, name } = parseWidgetId(widgetId)
     const state: WidgetState<TValue> = {