fix(script-editor,raw-app-editor): preserve AI chat across editor nav

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

frontend/src/lib/components/ScriptEditor.svelte

@@ -28,6 +28,7 @@
 	import JobLoader from './JobLoader.svelte'
 	import JobProgressBar from '$lib/components/jobs/JobProgressBar.svelte'
 	import { createEventDispatcher, getContext, onDestroy, onMount, untrack } from 'svelte'
+	import { beforeNavigate } from '$app/navigation'
 	import { Button } from './common'
 	import SplitPanesWrapper from './splitPanes/SplitPanesWrapper.svelte'
 	import WindmillIcon from './icons/WindmillIcon.svelte'
@@ -1203,6 +1204,24 @@
 		}
 	})
 
+	// Preserve the chat across the /scripts/add → /scripts/edit/{path} promotion
+	// (and same-script reloads): ScriptEditor unmounts + remounts on those
+	// transitions, and without this its onDestroy would saveAndClear the
+	// SCRIPT-mode conversation the user is still actively having about this same
+	// script.
+	let preserveChatOnDestroy = $state(false)
+	beforeNavigate(({ to }) => {
+		const dest = to?.url.pathname ?? ''
+		if (!dest.startsWith('/scripts/edit/')) return
+		const destPath = dest.slice('/scripts/edit/'.length)
+		const currentPath = aiChatManager.scriptEditorOptions?.path
+		// !currentPath: on /scripts/add, dest is /scripts/edit/{path} (initial save).
+		// destPath === currentPath: same script (e.g. query change / reload).
+		if (!currentPath || destPath === currentPath) {
+			preserveChatOnDestroy = true
+		}
+	})
+
 	onMount(async () => {
 		await inferSchema(code, { applyInitialArgs: true })
 		// Retry once if the initial inference failed silently (e.g. transient WASM
@@ -1211,7 +1230,12 @@
 		if (!validCode && code && lang) {
 			await inferSchema(code, { applyInitialArgs: true })
 		}
-		aiChatManager.saveAndClear()
+		// The previous instance's onDestroy may have preserved the chat for
+		// intra-script-editor nav; in that case mode is still SCRIPT and the
+		// conversation is intact. Skip saveAndClear so we don't blow it away.
+		if (aiChatManager.mode !== AIMode.SCRIPT) {
+			aiChatManager.saveAndClear()
+		}
 		aiChatManager.changeMode(AIMode.SCRIPT)
 	})
 
@@ -1298,8 +1322,10 @@
 		aiChatManager.scriptEditorShowDiffMode = undefined
 		aiChatManager.scriptEditorGetLintErrors = undefined
 		aiChatManager.scriptEditorOptions = undefined
-		aiChatManager.saveAndClear()
-		aiChatManager.changeMode(AIMode.NAVIGATOR)
+		if (!preserveChatOnDestroy) {
+			aiChatManager.saveAndClear()
+			aiChatManager.changeMode(AIMode.NAVIGATOR)
+		}
 		// Clean up debug mode
 		if (debugMode) {
 			stopDebugging()
@@ -1357,9 +1383,7 @@
 	// width (Svelte wires a ResizeObserver for bind:clientWidth).
 	let splitContainerWidth = $state(0)
 	const TEST_PANE_MIN_PX = 400
-	const testPaneMinPercent = $derived(
-		paneMinPercent(splitContainerWidth, TEST_PANE_MIN_PX)
-	)
+	const testPaneMinPercent = $derived(paneMinPercent(splitContainerWidth, TEST_PANE_MIN_PX))
 
 	// Raw user-controlled test size (what the splitter wrote, or what the
 	// toggle set). The size we actually pass to <Pane> is clamped to the

frontend/src/lib/components/raw_apps/RawAppEditor.svelte

@@ -21,7 +21,8 @@
 	import type { Modules } from './RawAppModules.svelte'
 	import { isRunnableByName, isRunnableByPath } from '../apps/inputType'
 	import { aiChatManager, AIMode } from '../copilot/chat/AIChatManager.svelte'
-	import { onMount, untrack } from 'svelte'
+	import { onDestroy, onMount, untrack } from 'svelte'
+	import { beforeNavigate } from '$app/navigation'
 	import type {
 		AppDatatableMetadata,
 		LintResult,
@@ -618,8 +619,30 @@
 		)
 	}
 
+	// Preserve the chat across the /apps_raw/add → /apps_raw/edit/{path} promotion
+	// (and same-app reloads): RawAppEditor unmounts + remounts on those
+	// transitions, and without this the fresh onMount's saveAndClear would blow
+	// away the APP-mode conversation the user is still actively having about this
+	// same app.
+	let preserveChatOnDestroy = $state(false)
+	beforeNavigate(({ to }) => {
+		const dest = to?.url.pathname ?? ''
+		if (!dest.startsWith('/apps_raw/edit/')) return
+		const destPath = dest.slice('/apps_raw/edit/'.length)
+		// !path: on /apps_raw/add, dest is /apps_raw/edit/{path} (initial deploy).
+		// destPath === path: same app.
+		if (!path || destPath === path) {
+			preserveChatOnDestroy = true
+		}
+	})
+
 	onMount(() => {
-		aiChatManager.saveAndClear()
+		// The previous instance may have preserved the chat for intra-app-editor
+		// nav; in that case mode is still APP and the conversation is intact. Skip
+		// saveAndClear so we don't blow it away.
+		if (aiChatManager.mode !== AIMode.APP) {
+			aiChatManager.saveAndClear()
+		}
 		aiChatManager.changeMode(AIMode.APP)
 		rawAppLintStore.enable()
 		loadSharedUi()
@@ -645,6 +668,16 @@
 		}
 	})
 
+	onDestroy(() => {
+		// Cross-app / leave-editor navigation resets to NAVIGATOR; same-app /
+		// add→edit navigation keeps the chat (the fresh onMount detects mode is
+		// still APP and skips its clearing saveAndClear).
+		if (!preserveChatOnDestroy) {
+			aiChatManager.saveAndClear()
+			aiChatManager.changeMode(AIMode.NAVIGATOR)
+		}
+	})
+
 	// Sync data with aiChatManager.datatableCreationPolicy (bidirectional)
 	$effect(() => {
 		// Read the current policy from aiChatManager
@@ -1637,8 +1670,9 @@
 											title="Build failed"
 											class="relative before:absolute before:inset-0 before:-z-10 before:rounded-md before:bg-surface before:content-['']"
 										>
-											<pre
-												class="overflow-auto whitespace-pre-wrap text-xs max-h-60">{buildError}</pre>
+											<pre class="overflow-auto whitespace-pre-wrap text-xs max-h-60"
+												>{buildError}</pre
+											>
 										</Alert>
 									</div>
 								{/if}