claude-code: add enableMcpIntegration

Add `enableMcpIntegration` option to merge MCP servers from
`programs.mcp.servers` into Claude Code configuration. Claude Code
servers take precedence over general MCP servers when both define
the same server name.

tests/modules/programs/claude-code/assertion.nix

@@ -47,7 +47,7 @@
   };
 
   test.asserts.assertions.expected = [
-    "`programs.claude-code.package` cannot be null when `mcpServers` is configured"
+    "`programs.claude-code.package` cannot be null when `mcpServers` or `enableMcpIntegration` is configured"
     "Cannot specify both `programs.claude-code.memory.text` and `programs.claude-code.memory.source`"
     "Cannot specify both `programs.claude-code.agents` and `programs.claude-code.agentsDir`"
     "Cannot specify both `programs.claude-code.commands` and `programs.claude-code.commandsDir`"

tests/modules/programs/claude-code/default.nix

@@ -2,6 +2,7 @@
   claude-code-basic = ./basic.nix;
   claude-code-full-config = ./full-config.nix;
   claude-code-mcp = ./mcp.nix;
+  claude-code-mcp-integration = ./mcp-integration.nix;
   claude-code-assertion = ./assertion.nix;
   claude-code-memory-management = ./memory-management.nix;
   claude-code-memory-from-source = ./memory-from-source.nix;

tests/modules/programs/claude-code/mcp-integration.nix

@@ -0,0 +1,72 @@
+{ config, ... }:
+
+{
+  programs = {
+    claude-code = {
+      package = config.lib.test.mkStubPackage {
+        name = "claude-code";
+        buildScript = ''
+          mkdir -p $out/bin
+          touch $out/bin/claude
+          chmod 755 $out/bin/claude
+        '';
+      };
+      enable = true;
+
+      enableMcpIntagretion = true;
+
+      mcpServers = {
+        github = {
+          type = "http";
+          url = "https://api.githubcopilot.com/mcp/";
+        };
+        filesystem = {
+          type = "stdio";
+          command = "npx";
+          args = [
+            "-y"
+            "@modelcontextprotocol/server-filesystem"
+            "/tmp"
+          ];
+        };
+      };
+    };
+    mcp = {
+      enable = true;
+      servers = {
+        filesystem = {
+          type = "stdio";
+          command = "npx";
+          args = [
+            "-y"
+            "@modelcontextprotocol/server-filesystem"
+            "/other-tmp"
+          ];
+        };
+        database = {
+          command = "npx";
+          args = [
+            "-y"
+            "@bytebase/dbhub"
+            "--dsn"
+            "postgresql://user:pass@localhost:5432/db"
+          ];
+          env = {
+            DATABASE_URL = "postgresql://user:pass@localhost:5432/db";
+          };
+        };
+        customTransport = {
+          type = "websocket";
+          url = "wss://example.com/mcp";
+          customOption = "value";
+          timeout = 5000;
+        };
+      };
+    };
+  };
+
+  nmt.script = ''
+    normalizedWrapper=$(normalizeStorePaths home-path/bin/claude)
+    assertFileContent $normalizedWrapper ${./expected-mcp-wrapper}
+  '';
+}