feat(sidebar): surface partial status for multi-container stacks (#1426)

Bulk stack-status aggregation collapsed a stack to "running" as soon as any
container was up, so a multi-container stack with crashed containers showed a
green UP pill and the degradation was invisible from the sidebar.

Add a crash-aware "partial" state: a stack is partial when at least one
container is running and at least one has genuinely failed (exited with a
non-zero code, dead, or crash-looping). Cleanly finished one-shot containers
(exit 0) and clean restart-policy cycling do not count, so an app with a
completed init job stays UP. The exit code is read from the container Status
string, so no extra inspect calls are needed.

Render partial as an amber PT pill with a hover tooltip showing the
running/total count, fold it into the Down filter (needs-attention), and treat
it as running for context-menu lifecycle actions so operators keep
stop/restart/update. The dashboard stack-health table, cross-node search rows,
and the command palette all pick up the new state through the shared status
surfaces.

frontend/src/components/sidebar/__tests__/StackRow.test.tsx

@@ -36,6 +36,26 @@ describe('StackRow', () => {
     expect(screen.getByText('--')).toBeInTheDocument();
   });
 
+  it('renders PT with the amber class for partial', () => {
+    const { container } = render(<StackRow {...base({ status: 'partial', running: 3, total: 5 })} />);
+    expect(screen.getByText('PT')).toBeInTheDocument();
+    expect(container.querySelector('.text-warning')).not.toBeNull();
+  });
+
+  it('wraps the partial pill in a hover tooltip', () => {
+    // jsdom does not mount the cursor-follow label, so assert the PT trigger is
+    // wrapped in the RowTooltip cursor-container; the visible "3/5 running"
+    // tooltip text is verified in the Playwright drive.
+    const { container } = render(<StackRow {...base({ status: 'partial', running: 3, total: 5 })} />);
+    expect(screen.getByText('PT').closest('[data-slot="cursor-container"]')).not.toBeNull();
+    expect(container.querySelector('[data-slot="cursor-container"]')).not.toBeNull();
+  });
+
+  it('does not wrap a non-partial pill in a tooltip', () => {
+    render(<StackRow {...base({ status: 'running' })} />);
+    expect(screen.getByText('UP').closest('[data-slot="cursor-container"]')).toBeNull();
+  });
+
   it('renders cyan rail only when active', () => {
     const { rerender } = render(<StackRow {...base({ isActive: false })} />);
     expect(screen.getByTestId('stack-row')).not.toHaveClass('bg-accent/[0.07]');