fix(deploy): Checkpoints — preserve STOPPED history, fix filter + placement

- Backend: rename deleteTerminalByAppAndEnvironment → deleteFailedByAppAndEnvironment.
  STOPPED rows were being wiped on every redeploy, so Checkpoints was always empty.
  Now only FAILED rows are pruned; STOPPED deployments are retained as restorable
  checkpoints (they still carry deployed_config_snapshot from their RUNNING window).
- UI filter: any deployment with a snapshot is a checkpoint (was RUNNING|DEGRADED only,
  which excluded the main case — the previous blue/green deployment now in STOPPED).
- UI placement: Checkpoints disclosure now renders inside IdentitySection, matching
  the design spec.

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

ui/src/pages/AppsTab/AppDeploymentPage/Checkpoints.tsx

@@ -15,15 +15,11 @@ export function Checkpoints({ deployments, versions, currentDeploymentId, onRest
   const [open, setOpen] = useState(false);
   const versionMap = new Map(versions.map((v) => [v.id, v]));
 
-  // Deployments that reached COMPLETE stage and captured a snapshot (RUNNING or DEGRADED).
-  // Exclude the currently-running one.
+  // Any deployment that captured a snapshot is restorable — that covers RUNNING,
+  // DEGRADED, and STOPPED (blue/green swap previous, user-stopped). Exclude the
+  // currently-running one and anything without a snapshot (FAILED, STARTING).
   const checkpoints = deployments
-    .filter(
-      (d) =>
-        d.deployedAt &&
-        (d.status === 'RUNNING' || d.status === 'DEGRADED') &&
-        d.id !== currentDeploymentId,
-    )
+    .filter((d) => d.deployedConfigSnapshot && d.id !== currentDeploymentId)
     .sort((a, b) => (b.deployedAt ?? '').localeCompare(a.deployedAt ?? ''));
 
   return (

ui/src/pages/AppsTab/AppDeploymentPage/IdentitySection.tsx

@@ -1,4 +1,4 @@
-import { useRef } from 'react';
+import { useRef, type ReactNode } from 'react';
 import { SectionHeader, Input, MonoText, Button } from '@cameleer/design-system';
 import type { App, AppVersion } from '../../../api/queries/admin/apps';
 import type { Environment } from '../../../api/queries/admin/environments';
@@ -25,11 +25,12 @@ interface IdentitySectionProps {
   stagedJar: File | null;
   onStagedJarChange: (file: File | null) => void;
   deploying: boolean;
+  children?: ReactNode;
 }
 
 export function IdentitySection({
   mode, environment, app, currentVersion,
-  name, onNameChange, stagedJar, onStagedJarChange, deploying,
+  name, onNameChange, stagedJar, onStagedJarChange, deploying, children,
 }: IdentitySectionProps) {
   const fileInputRef = useRef<HTMLInputElement>(null);
   const slug = app?.slug ?? slugify(name);
@@ -109,6 +110,7 @@ export function IdentitySection({
           )}
         </div>
       </div>
+      {children}
     </div>
   );
 }

ui/src/pages/AppsTab/AppDeploymentPage/index.tsx

@@ -467,7 +467,7 @@ export default function AppDeploymentPage() {
         </div>
       </div>
 
-      {/* ── Identity & Artifact ── */}
+      {/* ── Identity & Artifact (with Checkpoints for deployed apps) ── */}
       <IdentitySection
         mode={mode}
         environment={env}
@@ -478,17 +478,16 @@ export default function AppDeploymentPage() {
         stagedJar={stagedJar}
         onStagedJarChange={setStagedJar}
         deploying={deploymentInProgress}
-      />
-
-      {/* ── Checkpoints (deployed apps only) ── */}
-      {app && (
-        <Checkpoints
-          deployments={deployments}
-          versions={versions}
-          currentDeploymentId={currentDeployment?.id ?? null}
-          onRestore={handleRestore}
-        />
-      )}
+      >
+        {app && (
+          <Checkpoints
+            deployments={deployments}
+            versions={versions}
+            currentDeploymentId={currentDeployment?.id ?? null}
+            onRestore={handleRestore}
+          />
+        )}
+      </IdentitySection>
 
       {/* ── Config tabs ── */}
       <div className={styles.tabGroup}>