Remove MCP tab and per-project MCP UI from frontend

Claude Code manages MCP natively now (`claude mcp add/list/remove`,
`.mcp.json`, `/mcp`), so Triple-C's own MCP server library is redundant.

Deletes components/mcp/, hooks/useMcpServers.ts, the MCP sidebar tab and
rail icon, the per-project enable checkboxes on ProjectCard, the
mcpServers slice of the Zustand store, the four IPC wrappers, and the
McpServer/McpTransportType types.

Rust backend is untouched in this commit; the commands simply become
unreachable. Backend removal and the legacy container/network cleanup
follow separately.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src/lib/tauri-commands.ts

@@ -1,5 +1,5 @@
 import { invoke } from "@tauri-apps/api/core";
-import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, ImageUpdateInfo, McpServer, FileEntry, WebTerminalInfo, SttStatus, InstallOptions } from "./types";
+import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, ImageUpdateInfo, FileEntry, WebTerminalInfo, SttStatus, InstallOptions } from "./types";
 
 // Docker
 export const checkDocker = () => invoke<boolean>("check_docker");
@@ -64,15 +64,6 @@ export const sendAudioData = (sessionId: string, data: number[]) =>
 export const stopAudioBridge = (sessionId: string) =>
   invoke<void>("stop_audio_bridge", { sessionId });
 
-// MCP Servers
-export const listMcpServers = () => invoke<McpServer[]>("list_mcp_servers");
-export const addMcpServer = (name: string) =>
-  invoke<McpServer>("add_mcp_server", { name });
-export const updateMcpServer = (server: McpServer) =>
-  invoke<McpServer>("update_mcp_server", { server });
-export const removeMcpServer = (serverId: string) =>
-  invoke<void>("remove_mcp_server", { serverId });
-
 // Files
 export const listContainerFiles = (projectId: string, path: string) =>
   invoke<FileEntry[]>("list_container_files", { projectId, path });