feat: add MCP server support with global library and per-project toggles

Add Model Context Protocol (MCP) server configuration support. Users can
define MCP servers globally (new sidebar tab) and enable them per-project.
Enabled servers are injected into containers as MCP_SERVERS_JSON env var
and merged into ~/.claude.json by the entrypoint.

Backend: McpServer model, McpStore (JSON + atomic writes), 4 CRUD commands,
container injection with fingerprint-based recreation detection.
Frontend: MCP sidebar tab, McpPanel/McpServerCard components, useMcpServers
hook, per-project MCP checkboxes in ProjectCard config.

Co-Authored-By: Claude Opus 4.6 <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 } from "./types";
+import type { Project, ProjectPath, ContainerInfo, SiblingContainer, AppSettings, UpdateInfo, McpServer } from "./types";
 
 // Docker
 export const checkDocker = () => invoke<boolean>("check_docker");
@@ -50,6 +50,15 @@ export const closeTerminalSession = (sessionId: string) =>
 export const pasteImageToTerminal = (sessionId: string, imageData: number[]) =>
   invoke<string>("paste_image_to_terminal", { sessionId, imageData });
 
+// 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 });
+
 // Updates
 export const getAppVersion = () => invoke<string>("get_app_version");
 export const checkForUpdates = () =>