make selected resilient + snapshot args for React (#9298)

* fix(ResourceEditor): make `selected` resilient + snapshot args for React

Two issues surfaced via the React SDK (reactify wrapper re-spreads Svelte
props on every host re-render):

1. The bindable `selected` prop transiently resets to undefined on each
   re-spread, flipping `current` through undefined and unmounting the
   form (input loses focus on every keystroke). Rename the prop to
   `selectedProp` and derive `selected = selectedProp ?? effectiveWorkspace`
   so the fallback insulates the component without effects.

2. The onChange dispatch passed `current.args` (a `$state` proxy) directly,
   so React consumers diffing by reference or JSON.stringify saw the same
   value forever, and the effect only tracked the args reference (not
   nested mutations). Wrap with `$state.snapshot` to deep-track and emit
   a plain object.

The bootstrap effect is also restructured: it no longer writes `selected`
(the derived handles defaulting) and now guards on `selected in initialStates`
so workspace flips remain idempotent.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(ResourceEditor): declare effectiveWorkspace before use in selected

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/lib/components/ResourceEditor.svelte

@@ -36,7 +36,7 @@
 		onChange,
 		defaultValues = undefined,
 		workspace = undefined,
-		selected = $bindable()
+		selected: selectedProp = $bindable()
 	}: Props = $props()
 
 	type ResourceState = {
@@ -50,6 +50,10 @@
 	const dispatch = createEventDispatcher()
 
 	let effectiveWorkspace = $derived(workspace ?? $workspaceStore!)
+	// Fallback to `effectiveWorkspace` insulates against reactify-style
+	// parents that re-spread props without `selected` — otherwise it
+	// transiently resets and the form below remounts on every keystroke.
+	let selected = $derived(selectedProp ?? effectiveWorkspace)
 	let initialPath = path
 
 	// Per-workspace handles are driven by `useMany`. We track the workspace
@@ -205,28 +209,25 @@
 		})
 	)
 
-	// Bootstrap: ensure selected is set on mount (edit or new)
+	// New-resource bootstrap: seed empty state per workspace (edit mode
+	// is seeded by the lazy-fetch effect below).
 	$effect(() => {
-	    selected
-		if (!effectiveWorkspace) return
+		if (!selected) return
+		if (initialPath) return
+		if (selected in initialStates) return
 		untrack(() => {
-			if (selected !== undefined) return
-			selected = effectiveWorkspace
-			if (!initialPath) {
-				// New resource
-				const s: ResourceState = {
-					path: '',
-					description: '',
-					args: (defaultValues && Object.keys(defaultValues).length > 0
-						? defaultValues
-						: {}) as any,
-					labels: undefined,
-					wsSpecific: false
-				}
-				ensureHandle(effectiveWorkspace, s)
-				initialStates[effectiveWorkspace] = structuredClone(s)
-				existedInitially[effectiveWorkspace] = false
+			const s: ResourceState = {
+				path: '',
+				description: '',
+				args: (defaultValues && Object.keys(defaultValues).length > 0
+					? defaultValues
+					: {}) as any,
+				labels: undefined,
+				wsSpecific: false
 			}
+			ensureHandle(selected, s)
+			initialStates[selected] = structuredClone(s)
+			existedInitially[selected] = false
 		})
 	})
 
@@ -330,11 +331,9 @@
 
 	$effect(() => {
 		if (current)
-			// Snapshot args so the deep read establishes nested dependency
-			// tracking (the effect re-runs on mutations inside args, not
-			// just reference changes) and so consumers receive a plain
-			// object instead of a $state proxy — important for React
-			// integrations that diff by reference or JSON.stringify.
+			// $state.snapshot deep-reads (so the effect re-runs on nested
+			// args mutations) and returns a plain object (React consumers
+			// can't diff a $state proxy by reference or JSON.stringify).
 			onChange?.({
 				path: current.path,
 				args: $state.snapshot(current.args) as Record<string, any>,