Move Dockhand container management to its own top-level Docker page

Container management was buried inside the generic Integrations
browsing view, mixed in with five unrelated integration types behind
a single "pick any integration" dropdown. Give it a dedicated page,
matching how Servers & Tasks and DNS already get their own top-level
spot instead of living inside Integrations.

New web/src/pages/Docker.tsx reuses the existing, unchanged Dockhand
API routes and adapter (no server changes) — it just has its own
integration picker scoped to Dockhand only, rather than sharing
Integrations' any-type dropdown. Added a Docker nav item (right after
Integrations) and route.

Removed the Dockhand-specific state/handlers/table from Integrations
entirely; adding, editing, enabling/disabling, and deleting the
Dockhand credential itself still happens under Integrations -> Manage
integrations like every other integration. Selecting a Dockhand row in
Integrations' generic browsing dropdown now points to the Docker page
instead of rendering a container table there too.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/App.tsx

@@ -11,6 +11,7 @@ import Dns from "./pages/Dns";
 import ServersTasks from "./pages/ServersTasks";
 import ServerDetail from "./pages/ServerDetail";
 import Integrations from "./pages/Integrations";
+import Docker from "./pages/Docker";
 import Settings from "./pages/Settings";
 import NotificationSettings from "./pages/settings/NotificationSettings";
 import BadgeSettings from "./pages/settings/BadgeSettings";
@@ -72,6 +73,7 @@ export default function App() {
         <Route path="/ipam" element={<Ipam user={user} />} />
         <Route path="/secrets" element={<Secrets user={user} />} />
         <Route path="/integrations" element={<Integrations user={user} />} />
+        <Route path="/docker" element={<Docker user={user} />} />
         <Route
           path="/users"
           element={