Fix null checks in crash components

- Add null checks for breadcrumbs, active_flags, and stacktrace in
  IssueDetail.svelte before accessing .length
- Use nullish coalescing for frames in Stacktrace.svelte to prevent
  "Cannot read properties of undefined (reading 'length')" errors

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ghuntley

web/loom-web/src/lib/components/crash/IssueDetail.svelte

@@ -152,11 +152,13 @@
 				</div>
 			</section>
 
-			<section class="issue-section">
-				<Stacktrace stacktrace={issue.latest_event.stacktrace} />
-			</section>
+			{#if issue.latest_event.stacktrace}
+				<section class="issue-section">
+					<Stacktrace stacktrace={issue.latest_event.stacktrace} />
+				</section>
+			{/if}
 
-			{#if issue.latest_event.breadcrumbs.length > 0}
+			{#if issue.latest_event.breadcrumbs && issue.latest_event.breadcrumbs.length > 0}
 				<section class="issue-section">
 					<Breadcrumbs breadcrumbs={issue.latest_event.breadcrumbs} />
 				</section>
@@ -167,7 +169,7 @@
 					<UserContext user={issue.latest_event.user_context} />
 				{/if}
 
-				{#if Object.keys(issue.latest_event.active_flags).length > 0}
+				{#if issue.latest_event.active_flags && Object.keys(issue.latest_event.active_flags).length > 0}
 					<ActiveFlags flags={issue.latest_event.active_flags} />
 				{/if}
 			</div>

web/loom-web/src/lib/components/crash/Stacktrace.svelte

@@ -29,8 +29,9 @@
 	let expandedFrames = $state<Set<number>>(new Set());
 	let showAllFrames = $state(false);
 
-	const inAppFrames = $derived(stacktrace.frames.filter((f) => f.in_app));
-	const displayedFrames = $derived(showAllFrames ? stacktrace.frames : inAppFrames);
+	const frames = $derived(stacktrace?.frames ?? []);
+	const inAppFrames = $derived(frames.filter((f) => f.in_app));
+	const displayedFrames = $derived(showAllFrames ? frames : inAppFrames);
 
 	function toggleFrame(index: number) {
 		const newSet = new Set(expandedFrames);
@@ -57,7 +58,7 @@
 		<h3 class="stacktrace-title">{title}</h3>
 		<div class="stacktrace-controls">
 			<span class="frame-count">
-				{displayedFrames.length} of {stacktrace.frames.length} frames
+				{displayedFrames.length} of {frames.length} frames
 			</span>
 			<button class="control-btn" onclick={() => (showAllFrames = !showAllFrames)}>
 				{showAllFrames ? 'App only' : 'All frames'}