refactor(decnet_web/DeckyFleet): move DeployWizard out

Lift the multi-step deploy wizard (~520 LOC) plus its private
INI-builder helpers (PLACEHOLDER_LINES, b64encodeUtf8, buildIni,
PickMode type) into their own file. Verbatim move; the
underscore-prefixed helpers drop the leading underscore now that
they're file-local rather than competing with hoisted parent
constants.

- New DeckyFleet/DeployWizard.tsx
- DeployWizard.test.tsx covers the closed render guard, the
  open-at-step-0 archetype list, NEXT-disabled-until-archetype,
  and CANCEL -> onClose. ServiceConfigFields is vi.mock'd to a
  stub since it pulls schemas via api.get() that are out of
  scope for these tests.
- DeckyFleet.tsx loses the wizard plus the now-unused imports
  (DEFAULT_SERVICES, Modal, PickIcon, ServiceConfigFields and
  its type aliases).

decnet_web/src/components/DeckyFleet/DeployWizard.test.tsx

@@ -0,0 +1,84 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { DeployWizard } from './DeployWizard';
+import type { Archetype } from './types';
+
+// ServiceConfigFields fetches the per-service schema; replace with a stub
+// so the wizard tests don't need MSW handlers for that side-channel.
+vi.mock('../ServiceConfigFields', async () => {
+  const actual = await vi.importActual<object>('../ServiceConfigFields');
+  return {
+    ...actual,
+    default: () => null,
+  };
+});
+
+const archetypes: Archetype[] = [
+  { slug: 'web-server', name: 'Web Server', services: ['http', 'https'], icon: 'globe' },
+  { slug: 'database', name: 'Database', services: ['postgres'], icon: 'database' },
+];
+
+describe('DeployWizard', () => {
+  it('renders nothing meaningful when closed', () => {
+    render(
+      <DeployWizard
+        open={false}
+        onClose={() => {}}
+        onComplete={() => {}}
+        archetypes={archetypes}
+        fleetSize={0}
+      />,
+    );
+    expect(screen.queryByText('DEPLOY NEW DECKIES')).not.toBeInTheDocument();
+  });
+
+  it('opens at step 0 with archetype list rendered', () => {
+    render(
+      <DeployWizard
+        open
+        onClose={() => {}}
+        onComplete={() => {}}
+        archetypes={archetypes}
+        fleetSize={0}
+      />,
+    );
+    expect(screen.getByText('DEPLOY NEW DECKIES')).toBeInTheDocument();
+    expect(screen.getByText('Web Server')).toBeInTheDocument();
+    expect(screen.getByText('Database')).toBeInTheDocument();
+  });
+
+  it('disables NEXT until an archetype is selected', async () => {
+    const user = userEvent.setup();
+    render(
+      <DeployWizard
+        open
+        onClose={() => {}}
+        onComplete={() => {}}
+        archetypes={archetypes}
+        fleetSize={0}
+      />,
+    );
+    const nextBtn = screen.getByText('NEXT →') as HTMLButtonElement;
+    expect(nextBtn.disabled).toBe(true);
+
+    await user.click(screen.getByText('Web Server'));
+    expect(nextBtn.disabled).toBe(false);
+  });
+
+  it('CANCEL button invokes onClose', async () => {
+    const onClose = vi.fn();
+    const user = userEvent.setup();
+    render(
+      <DeployWizard
+        open
+        onClose={onClose}
+        onComplete={() => {}}
+        archetypes={archetypes}
+        fleetSize={0}
+      />,
+    );
+    await user.click(screen.getByText('CANCEL'));
+    expect(onClose).toHaveBeenCalled();
+  });
+});