feat: keep an agent's in-progress edits on the agent

Editing a linked agent forks it into the step, which is what makes the
edits runnable there — but the agent is what is being edited, so that is
where the unsaved state belongs. The edit is mirrored into the agent's own
resource draft as it is made.

It then survives leaving the flow, shows the agent as drafted wherever it
appears, and is what evals run when asked to run the draft rather than what
is deployed. Deploying or cancelling clears it; opening Edit without
changing anything does not mark the agent as drafted.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/lib/components/flows/content/AgentResourceBar.svelte

@@ -7,6 +7,7 @@
 	import TextInput from '$lib/components/text_input/TextInput.svelte'
 	import { AiEvalsService, ResourceService, type InputTransform } from '$lib/gen'
 	import { workspaceStore } from '$lib/stores'
+	import { UserDraftDbSyncer } from '$lib/userDraftDbSyncer.svelte'
 	import { sendUserToast } from '$lib/toast'
 	import { Bot, Save, Unlink, Pencil } from 'lucide-svelte'
 	import {
@@ -330,6 +331,8 @@
 		const path = editingPath
 		try {
 			if (await persist(path)) {
+				// Deployed: the draft described what is now the agent, so it describes nothing.
+				clearDraft(path)
 				sendUserToast(`Updated agent ${path}`)
 			}
 		} catch (e) {
@@ -413,6 +416,67 @@
 		}
 	}
 
+	/**
+	 * Mirror the edit in progress into the agent's own draft.
+	 *
+	 * The step is forked while you edit it, which is what makes the edits runnable here — but the
+	 * agent is what is being edited, so that is where the unsaved state belongs. Kept there, it
+	 * survives closing the flow, shows the agent as drafted wherever it appears, and is what evals
+	 * run when you ask them to run the draft rather than what is deployed.
+	 */
+	function mirrorEditToDraft(path: string) {
+		if (!ws) return
+		UserDraftDbSyncer.save({
+			workspace: ws,
+			itemKind: 'resource',
+			path,
+			value: {
+				path,
+				description: '',
+				args: inputTransformsToAgentConfig(inputTransforms, tools),
+				labels: undefined,
+				wsSpecific: false
+			}
+		})
+	}
+
+	/** Drop it: the edit was saved, so the draft describes nothing that is not deployed, or it was
+	 *  abandoned, so it describes nothing at all. */
+	function clearDraft(path: string) {
+		if (!ws) return
+		UserDraftDbSyncer.save({ workspace: ws, itemKind: 'resource', path, value: null })
+	}
+
+	$effect(() => {
+		const path = editingPath
+		// Read so an edit to either re-runs this.
+		const brain = JSON.stringify(inputTransforms)
+		const toolset = JSON.stringify(tools)
+		untrack(() => {
+			if (!path || (brain === mirroredBrain && toolset === mirroredTools)) return
+			// The state the fork opened on is what the agent already holds: mirroring it would
+			// mark an untouched agent as drafted.
+			if (mirroredBrain === undefined) {
+				mirroredBrain = brain
+				mirroredTools = toolset
+				return
+			}
+			mirroredBrain = brain
+			mirroredTools = toolset
+			mirrorEditToDraft(path)
+		})
+	})
+	let mirroredBrain: string | undefined = $state(undefined)
+	let mirroredTools: string | undefined = $state(undefined)
+	$effect(() => {
+		if (!editingPath) {
+			untrack(() => {
+				mirroredBrain = undefined
+				mirroredTools = undefined
+			})
+		}
+	})
+
 	// Cancel discards the edits and re-links the step, leaving the agent untouched. Diverging from
 	// the agent is Unlink's job, on the linked card. Edit kept this flow's `tool_inputs` off the
 	// forked tools rather than folding them in, so they survive the round trip as overrides.
@@ -423,6 +487,7 @@
 		if (!path) {
 			return
 		}
+		clearDraft(path)
 		agent = path
 		tools = []
 		inputTransforms = flowLocalInputs(inputTransforms)
@@ -493,8 +558,16 @@
 			<div class="flex items-start gap-2">
 				<Pencil size={16} class="text-primary shrink-0 mt-0.5" />
 				<div class="min-w-0 flex-1">
-					<div class="truncate text-xs font-medium" title={editingPath}>{editingPath}</div>
+					<div class="flex items-center gap-2 min-w-0">
+						<span class="truncate text-xs font-medium" title={editingPath}>{editingPath}</span>
+						{#if mirroredBrain !== undefined}
+							<Badge color="yellow">unsaved changes</Badge>
+						{/if}
+					</div>
 					<div class="text-2xs text-secondary">
+						{#if mirroredBrain !== undefined}
+							Kept on the agent as a draft, so they survive leaving this flow.
+						{/if}
 						Saving affects every flow using it<Tooltip small placement="bottom">
 							{#snippet text()}
 								Save changes writes back to the saved agent and re-links this step, so every flow