feat(cc-config): add and remove MCP servers through the claude CLI

Mutation goes through `claude mcp add|remove`, never a direct edit of
~/.claude.json — the running CLI rewrites that file concurrently, so a
dashboard write would race it. Reads stay on readMcpServers.

The plan specified a --url flag; the real CLI (v2.1.266) has none —
commandOrUrl is positional, and --header must trail it or the variadic
flag swallows the url. Built against the verified shape.

client/src/lib/api.ts

@@ -97,6 +97,8 @@
  * - `CcPluginsResponse` — exported API; see TSDoc on the symbol for behavior.
  * - `CcMcpServer` — exported API; see TSDoc on the symbol for behavior.
  * - `CcMcpResponse` — exported API; see TSDoc on the symbol for behavior.
+ * - `CcMcpScope` — exported API; see TSDoc on the symbol for behavior.
+ * - `CcMcpAddArgs` — exported API; see TSDoc on the symbol for behavior.
  * - `CcHookEntry` — exported API; see TSDoc on the symbol for behavior.
  * - `CcHookSource` — exported API; see TSDoc on the symbol for behavior.
  * - `CcSettingsSource` — exported API; see TSDoc on the symbol for behavior.
@@ -1404,6 +1406,28 @@ export const api = {
      * @returns {@link CcMcpResponse} — servers split into `user`/`projectScoped`.
      */
     mcp: () => request<CcMcpResponse>("/cc-config/mcp"),
+    /**
+     * POST /api/cc-config/mcp/add - add an MCP server via `claude mcp add`.
+     * Either `url` (http/sse) or `command`+`args` (stdio) must be given, not
+     * both. `scope` is required — `user` or `project` only, never the
+     * settings union's third `project-local` value.
+     * @returns {@link CcCliResult} — the CLI's stdout/stderr on success.
+     */
+    mcpAdd: (args: CcMcpAddArgs) =>
+      request<CcCliResult>("/cc-config/mcp/add", {
+        method: "POST",
+        body: JSON.stringify(args),
+      }),
+    /**
+     * POST /api/cc-config/mcp/remove - remove an MCP server via
+     * `claude mcp remove`. `scope` narrows which config layer to remove
+     * from; omit it to let the CLI find the server wherever it exists.
+     */
+    mcpRemove: (name: string, scope?: CcMcpScope) =>
+      request<CcCliResult>("/cc-config/mcp/remove", {
+        method: "POST",
+        body: JSON.stringify({ name, scope }),
+      }),
     /**
      * GET /api/cc-config/hooks - hook entries from every settings.json layer.
      * @returns `{ items }` — one {@link CcHookSource} per settings layer.
@@ -2647,6 +2671,25 @@ export interface CcMcpResponse {
   projectScoped: CcMcpServer[];
 }
 
+/** Scope the `claude mcp` CLI accepts from this form. Deliberately not the
+ *  three-value settings union — the CLI's own third scope (`local`) is a
+ *  different axis and is not offered here. */
+export type CcMcpScope = "user" | "project";
+
+/** Body of POST /api/cc-config/mcp/add. Either `url` (http/sse) or
+ *  `command`+`args` (stdio) is required, never both. `env` is stdio-only;
+ *  `headers` is http/sse-only. */
+export interface CcMcpAddArgs {
+  name: string;
+  scope: CcMcpScope;
+  transport?: "http" | "sse";
+  url?: string;
+  headers?: Record<string, string>;
+  command?: string;
+  args?: string[];
+  env?: Record<string, string>;
+}
+
 /** One hook binding within a settings.json `hooks` block. */
 export interface CcHookEntry {
   /** Tool-name matcher pattern (e.g. "Bash", "Edit|Write", or "*"). */