feat(snapshots): Show diff_threshold in snapshot detail header

Surface the optional diff_threshold from the snapshot manifest in the
API response and display it in the header next to the branch name when
set. This lets users see what comparison precision was configured for
a given snapshot.

Refs EME-406
Co-Authored-By: Claude <noreply@anthropic.com>

Author: NicoHinderling

src/sentry/preprod/api/endpoints/preprod_artifact_snapshot.py

@@ -434,6 +434,7 @@ def get(self, request: Request, organization: Organization, snapshot_id: str) ->
                 errored_count=len(categorized.errored),
                 comparison_run_info=run_info,
                 approval_info=approval_info,
+                diff_threshold=manifest.diff_threshold,
             ).dict()
         )
 

src/sentry/preprod/api/models/snapshots/project_preprod_snapshot_models.py

@@ -97,5 +97,7 @@ class SnapshotDetailsApiResponse(BaseModel):
 
     approval_info: SnapshotApprovalInfo | None = None
 
+    diff_threshold: float | None = None
+
 
 # TODO: POST request in the future when we migrate away from current schemas

static/app/views/preprod/snapshots/header/snapshotHeaderContent.tsx

@@ -7,7 +7,13 @@ import {ExternalLink} from '@sentry/scraps/link';
 import {Text} from '@sentry/scraps/text';
 
 import * as Layout from 'sentry/components/layouts/thirds';
-import {IconCommit, IconPullRequest, IconShow, IconStack} from 'sentry/icons';
+import {
+  IconCommit,
+  IconPullRequest,
+  IconSettings,
+  IconShow,
+  IconStack,
+} from 'sentry/icons';
 import type {SVGIconProps} from 'sentry/icons/svgIcon';
 import {t} from 'sentry/locale';
 import type {Theme} from 'sentry/utils/theme';
@@ -66,7 +72,8 @@ export function SnapshotHeaderContent({
     <Layout.HeaderContent>
       <Layout.Title>{t('Snapshot')}</Layout.Title>
 
-      {vcsItems.length > 0 && (
+      {(vcsItems.length > 0 ||
+        (data.diff_threshold !== null && data.diff_threshold !== undefined)) && (
         <Flex align="center" gap="lg" wrap="wrap">
           {vcsItems.map(item => (
             <Flex align="center" gap="xs" key={item.key}>
@@ -82,6 +89,14 @@ export function SnapshotHeaderContent({
               )}
             </Flex>
           ))}
+          {data.diff_threshold !== null && data.diff_threshold !== undefined && (
+            <Flex align="center" gap="xs">
+              <IconSettings size="xs" />
+              <Text size="sm" variant="muted">
+                {t('Diff threshold: %s%%', (data.diff_threshold * 100).toFixed(1))}
+              </Text>
+            </Flex>
+          )}
         </Flex>
       )}
 

static/app/views/preprod/types/snapshotTypes.ts

@@ -52,6 +52,8 @@ export interface SnapshotDetailsApiResponse {
 
   approval_info?: SnapshotApprovalInfo | null;
 
+  diff_threshold?: number | null;
+
   // Diff fields
   added: SnapshotImage[];
   added_count: number;