fix: keep fleet prune estimate bytes after a target timeout (#1783)

* fix: keep fleet prune estimate bytes after a target timeout

Accumulate successful per-target reclaimable bytes on both the local
serial loop and the remote fan-out, mark partial nodes, and surface that
state in the Fleet prune card instead of zeroing the whole node.

* test: clarify zero-byte partial estimate card case

Rename the FleetPruneCard assertion so it matches fold semantics:
partial with zero bytes means a successful zero-byte target plus a failure,
not an all-failed node.

* fix: keep fleet prune estimate resilient on init and partial errors

Guard DockerController init so a deleted-node race cannot 500 the whole
fleet estimate, surface partial-node failure text in the card row title,
and pin the generic-rejection partial path with a fast route test.

* test: destroy reverse-route connect-ack sockets on teardown

Unguarded accepted sockets could emit a late ECONNRESET after assertions passed, failing the Backend Vitest job with zero assertion failures.

frontend/src/components/fleet/FleetActions/cards/FleetPruneCard.test.tsx

@@ -71,10 +71,61 @@ beforeEach(() => {
 it('keeps destructive prune disabled until an itemized dry run is reviewed', async () => {
   render(<FleetPruneCard nodes={nodes} />);
   await waitFor(() => expect(screen.getByText('~ 4 KB reclaimable')).toBeInTheDocument());
+  expect(screen.queryByText(/· partial/)).not.toBeInTheDocument();
+  expect(screen.getByText('OK')).toBeInTheDocument();
+  expect(screen.queryByText('PART')).not.toBeInTheDocument();
   expect(screen.getByRole('button', { name: 'Prune fleet' })).toBeDisabled();
   expect(screen.getByText(/Run Dry run to unlock Prune fleet/)).toBeInTheDocument();
 });
 
+it('marks partial estimates with a PART pill and blast suffix', async () => {
+  mockedFetch.mockImplementation((url: string) => {
+    if (url === '/fleet/prune/estimate') {
+      return Promise.resolve(jsonResponse(200, {
+        totalBytes: 500,
+        perNode: [{
+          nodeId: 1,
+          nodeName: 'central',
+          reclaimableBytes: 500,
+          reachable: true,
+          partial: true,
+          error: 'Docker daemon is busy. Please try again in a moment.',
+        }],
+      }));
+    }
+    return Promise.resolve(jsonResponse(404, {}));
+  });
+
+  render(<FleetPruneCard nodes={nodes} />);
+  await waitFor(() => expect(screen.getByText('~ 500 Bytes reclaimable · partial')).toBeInTheDocument());
+  expect(screen.getByText('PART')).toBeInTheDocument();
+  expect(screen.queryByText('OK')).not.toBeInTheDocument();
+  expect(screen.getByTitle('Docker daemon is busy. Please try again in a moment.')).toBeInTheDocument();
+});
+
+it('shows 0 reclaimable · partial when successful targets report zero bytes', async () => {
+  mockedFetch.mockImplementation((url: string) => {
+    if (url === '/fleet/prune/estimate') {
+      return Promise.resolve(jsonResponse(200, {
+        totalBytes: 0,
+        perNode: [{
+          nodeId: 1,
+          nodeName: 'central',
+          reclaimableBytes: 0,
+          reachable: true,
+          partial: true,
+          error: 'Docker daemon is busy. Please try again in a moment.',
+        }],
+      }));
+    }
+    return Promise.resolve(jsonResponse(404, {}));
+  });
+
+  render(<FleetPruneCard nodes={nodes} />);
+  await waitFor(() => expect(screen.getByText('0 reclaimable · partial')).toBeInTheDocument());
+  expect(screen.getByText('PART')).toBeInTheDocument();
+});
+
 it('drops the unlock footer once dry run review is valid', async () => {
   const user = userEvent.setup();
   mockedFetch.mockImplementation((url: string) => {

frontend/src/components/fleet/FleetActions/cards/FleetPruneCard.tsx

@@ -28,6 +28,7 @@ interface PruneEstimateNode {
   reclaimableBytes: number;
   reachable: boolean;
   error?: string;
+  partial?: boolean;
 }
 
 interface PruneEstimateResponse {
@@ -287,8 +288,10 @@ export function FleetPruneCard({ nodes }: Props) {
     if (estimate.kind === 'loading') return '~ estimating…';
     if (estimate.kind === 'unavailable') return '~ estimate unavailable';
     if (estimate.kind === 'ready') {
-      if (estimate.data.totalBytes === 0) return '0 reclaimable';
-      return `~ ${formatBytes(estimate.data.totalBytes)} reclaimable`;
+      const partial = estimate.data.perNode.some((node) => node.partial);
+      const suffix = partial ? ' · partial' : '';
+      if (estimate.data.totalBytes === 0) return `0 reclaimable${suffix}`;
+      return `~ ${formatBytes(estimate.data.totalBytes)} reclaimable${suffix}`;
     }
     return 'awaiting target';
   }, [targets.size, estimate]);
@@ -396,13 +399,21 @@ function EstimateSection({ estimate }: { estimate: EstimateState }) {
       <div className="rounded border border-card-border/60 bg-card/40 p-2 shadow-[inset_0_2px_4px_0_oklch(0_0_0_/_0.35)]">
         <ul className="space-y-1">
           {visible.map((node) => (
-            <li key={node.nodeId} className="flex items-center gap-2">
+            <li
+              key={node.nodeId}
+              className="flex items-center gap-2"
+              title={node.error}
+            >
               <span className={cn(
                 KICKER,
                 'inline-flex shrink-0 items-center rounded-sm border px-1 py-0.5',
-                node.reachable ? 'border-success/40 bg-success/10 text-success' : 'border-stat-subtitle/40 bg-card text-stat-subtitle',
+                node.reachable
+                  ? (node.partial
+                    ? 'border-warning/40 bg-warning/10 text-warning'
+                    : 'border-success/40 bg-success/10 text-success')
+                  : 'border-stat-subtitle/40 bg-card text-stat-subtitle',
               )}>
-                {node.reachable ? 'OK' : '--'}
+                {node.reachable ? (node.partial ? 'PART' : 'OK') : '--'}
               </span>
               <span className="min-w-0 flex-1 truncate font-mono text-[11px] text-stat-value">{node.nodeName}</span>
               <span className={cn(KICKER, 'shrink-0 tabular-nums', node.reachable ? 'text-stat-subtitle' : 'text-stat-icon')}>