Subgraph instances added from the node search share one promoted widget value

## Summary Every `SubgraphNode` instance created through the node search / node library shares a single promoted-widget entry in `widgetValueStore`, keyed `<rootGraphId>:-1:<inputName>`. Editing a promoted widget on one instance changes it on every other instance of the same subgraph, and deleting one can delete the other's state. ## Root cause `SubgraphNode._setWidget` computes the widget id from the node's id at construction time: ```ts // src/lib/litegraph/src/subgraph/SubgraphNode.ts:660 const id = widgetId(this.rootGraph.id, this.id, subgraphInput.name) input.widgetId = id ``` The registered node class for a subgraph type is built with `instanceData.id = -1`: ```ts // src/services/subgraphService.ts:22-32 const instanceData: ExportedSubgraphInstance = { id: -1, type: exportedSubgraph.id, ... } ``` So `LiteGraph.createNode(subgraphId)` produces a node whose id is `-1`, promotion runs during construction, and `input.widgetId` is baked as `<rootGraphId>:-1:<name>`. `LGraph.add()` then assigns the real node id, but nothing re-keys `input.widgetId`. `SubgraphNode.configure()` does re-key (via `_internalConfigureAfterSlots` -> `_resolveInputWidget` -> `_setWidget`), which is why loading and pasting a workflow are unaffected. The node-search path never calls `configure`: ```ts // src/services/litegraphService.ts:930-951 (addNodeOnGraph) const node = LiteGraph.createNode(nodeDef.name, nodeDef.display_name, options) ... graph.add(node, addOptions) return node ``` ## Reproduction Add the same subgraph twice from the node library / node search, then change a promoted widget value on one copy. The other copy changes too. Unit reproduction (green on `main` today, pinned as a tripwire in `src/lib/litegraph/src/subgraph/SubgraphDuplicateDeleteOrder.test.ts`): ```ts const first = addWithoutConfigure() const second = addWithoutConfigure() expect(first.id).not.toBe(second.id) expect(promotedId(first)).toBe(promotedId(second)) // both `<rootGraphId>:-1:value` useWidgetValueStore().setValue(promotedId(first), 999) expect(promotedValueOf(second)).toBe(999) ``` ## Impact Violates the ECS migration invariant I4 (no ambiguous entity ownership across graphs): a duplicate id lets one instance overwrite another's entity. Two instances of one shared definition are indistinguishable to the widget store. ## Suggested fix Re-key promoted widget ids when the node id is assigned (an `onAdded` rebind, or `rebuildInputWidgetBindings()` after `LGraph.add`), or refuse to register promoted widget state while the node id is `UNASSIGNED_NODE_ID`.