feat(mcp): enhance MCP transport support and add server management UI

- Extend McpTransport to support "sse" in schemas.
- Refactor McpToolClient to handle both "streamable_http" and "sse" transports.
- Introduce McpServerDialog for managing MCP server configurations, including transport settings and tool synchronization.
- Replace McpServersSection with the new dialog component for improved server management.
- Add tests for MCP transport handling and server dialog functionality.

frontend/src/lib/api.ts

@@ -399,7 +399,7 @@ export type McpServer = {
   id: string;
   name: string;
   description: string;
-  transport: "streamable_http";
+  transport: "streamable_http" | "sse";
   url: string;
   timeoutSeconds: number;
   headers: Record<string, string>;
@@ -438,6 +438,8 @@ export const mcpServersApi = {
     request<McpSyncResult>(`/api/mcp-servers/${id}/sync`, {
       method: "POST",
     }),
+  tools: (id: string) =>
+    request<Tool[]>(`/api/mcp-servers/${id}/tools`),
   remove: (id: string) =>
     request<{ ok: boolean }>(`/api/mcp-servers/${id}`, {
       method: "DELETE",