fix: enable tool activation for Claude clients in mcp-add

The mcp-add command was incorrectly skipping tool activation for Claude
clients based on the assumption that "Claude clients auto-refresh their
tool list". This assumption is incorrect.

When mcp-add is called with activate=true, tools were added to
g.toolRegistrations (accessible via mcp-exec) but NOT to g.mcpServer
(required for native MCP tool calls). This caused:

- mcp-add chromedev → success (26 tools registered)
- mcp-exec chromedev:list_pages → works (uses toolRegistrations)
- native call to chromedev:list_pages → "unknown tool" error

The fix removes the Claude client exclusion, allowing updateServerCapabilities()
to call g.mcpServer.AddTool() for all clients.

Related to #278 (tool-name-prefix dispatch fix)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: null-runner

pkg/gateway/mcpadd.go

@@ -209,9 +209,9 @@ func addServerHandler(g *Gateway, clientConfig *clientConfig) mcp.ToolHandler {
 		}
 		clientNameLower := strings.ToLower(clientName)
 
-		// Only activate tools if activate is true AND client name doesn't contain "claude"
-		// (Claude clients auto-refresh their tool list, so they don't need explicit activation)
-		shouldActivate := params.Activate && !strings.Contains(clientNameLower, "claude")
+		// Activate tools if requested - all clients need explicit activation
+		// (Removed incorrect assumption that Claude auto-refreshes tool list)
+		shouldActivate := params.Activate // Claude clients also need explicit activation
 
 		if shouldActivate {
 			// Now update g.mcpServer with the new capabilities