Trim the Servers page down to a server list + add-server flow

Scheduled-task browsing/editing already lives on each server's detail
page (ServerDetail.tsx), so the overview page's filters, task-group
listing, and add/edit-task form were pure duplication -- the only
things it needs to do are list servers (as clickable cards) and let
an admin register new ones / issue or rotate agent tokens.

Renamed ServersTasks.tsx -> Servers.tsx to match its new, narrower
scope; updated the nav label, route, and ServerDetail's back-link
text from "Servers & Tasks" to "Servers" accordingly. No server-side
or API changes -- this only removes now-redundant frontend code.

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

web/src/App.tsx

@@ -8,7 +8,7 @@ import AuditLog from "./pages/AuditLog";
 import Secrets from "./pages/Secrets";
 import Ipam from "./pages/Ipam";
 import Dns from "./pages/Dns";
-import ServersTasks from "./pages/ServersTasks";
+import Servers from "./pages/Servers";
 import ServerDetail from "./pages/ServerDetail";
 import Integrations from "./pages/Integrations";
 import Docker from "./pages/Docker";
@@ -72,7 +72,7 @@ export default function App() {
     <AppShell user={user}>
       <Routes>
         <Route path="/" element={<Dashboard user={user} />} />
-        <Route path="/servers" element={<ServersTasks user={user} />} />
+        <Route path="/servers" element={<Servers user={user} />} />
         <Route path="/servers/:id" element={<ServerDetail user={user} />} />
         <Route path="/dns" element={<Dns user={user} />} />
         <Route path="/ipam" element={<Ipam user={user} />} />