refactor(web): simplify AddAgentSheet by removing Stepper and updating layout

- Removed the Stepper component from AddAgentSheet, transitioning to a single form layout for agent creation.
- Updated the component's description and adjusted the UI elements for improved clarity and user experience.
- Enhanced the input fields and layout to streamline the agent installation invite process.

Co-authored-by: Cursor <[email protected]>

apps/web/src/routes/_auth/agents/$id.tsx

@@ -235,24 +235,6 @@ function AgentDetailPage() {
             <AlertDescription>{a.last_apply_error}</AlertDescription>
           </Alert>
         ) : null}
-        {a.status === 'pending' ? (
-          <Alert variant="warning">
-            <CircleAlertIcon />
-            <AlertTitle>Ожидает approve</AlertTitle>
-            <AlertDescription>
-              Агент записался, но политика не выдаётся до одобрения.
-            </AlertDescription>
-          </Alert>
-        ) : null}
-        {a.status === 'invited' ? (
-          <Alert variant="info">
-            <CircleAlertIcon />
-            <AlertTitle>Invited</AlertTitle>
-            <AlertDescription>
-              Скопируйте install-команду и выполните на хосте.
-            </AlertDescription>
-          </Alert>
-        ) : null}
 
         <DetailPanel.Metrics
           cards={[