feat(cortex-tui): use interactive panel for /mcp instead of modal

Change the /mcp command and KeyAction::OpenMcp to use the interactive
mode (displayed in the input area) instead of the modal overlay system.
This provides a consistent UX with the /settings command which already
uses this pattern.

Changes:
- ModalType::McpManager now enters interactive mode using build_mcp_selector
- KeyAction::OpenMcp uses interactive mode instead of modal_stack.push
- Implement McpServerAction handler to display server status on selection

Author: factorydroid

cortex-tui/src/runner/event_loop.rs

@@ -1978,10 +1978,11 @@ impl EventLoop {
                 self.open_sessions_modal();
             }
             KeyAction::OpenMcp => {
-                // Open MCP manager modal
-                // MCP servers would come from a dedicated MCP manager in production
-                let servers = Vec::new(); // Placeholder - MCP integration pending
-                self.open_mcp_manager(servers);
+                // Open MCP manager using interactive mode (like settings panel)
+                use crate::interactive::builders::build_mcp_selector;
+                let servers = self.app_state.mcp_servers.clone();
+                let interactive = build_mcp_selector(&servers);
+                self.app_state.enter_interactive_mode(interactive);
             }
 
             // Transcript
@@ -4127,9 +4128,11 @@ impl EventLoop {
                         self.open_sessions_modal();
                     }
                     ModalType::McpManager => {
-                        // Get MCP servers from app state
+                        // Use interactive mode for MCP servers (like settings panel)
+                        use crate::interactive::builders::build_mcp_selector;
                         let servers = self.app_state.mcp_servers.clone();
-                        self.open_mcp_manager(servers);
+                        let interactive = build_mcp_selector(&servers);
+                        self.app_state.enter_interactive_mode(interactive);
                     }
                     ModalType::Form(cmd_name) => {
                         // Some commands use interactive mode instead of forms
@@ -6021,7 +6024,34 @@ impl EventLoop {
                 return false;
             }
             InteractiveAction::McpServerAction => {
-                // TODO: handle MCP server action (start/stop/restart)
+                // Handle MCP server selection
+                if item_id == "__add__" {
+                    // Show add server form
+                    self.app_state
+                        .toasts
+                        .info("Use /mcp add <name> <command> [args] to add a server");
+                    return false;
+                }
+
+                // Find the selected server and toggle its state
+                let server = self
+                    .app_state
+                    .mcp_servers
+                    .iter()
+                    .find(|s| s.name == item_id);
+
+                if let Some(server) = server {
+                    // For now show the server status, actual start/stop would need MCP integration
+                    let status_text = server.status.text();
+                    self.app_state.toasts.info(&format!(
+                        "{}: {} ({} tools)",
+                        item_id, status_text, server.tool_count
+                    ));
+                } else {
+                    self.app_state
+                        .toasts
+                        .error(&format!("Server not found: {}", item_id));
+                }
                 return false;
             }
             InteractiveAction::AddContextFiles => {