Bundle creation: allow users to deselect tools from configurations

[ObnoxiousProxy]

• Motivation:
  Users need finer control to exclude certain tools during bundle creation.

• Proposed solution:
  Add a tool selection step to frontend/src/features/bundle-mcp/components/bundle-mcp-stepper-form.tsx to optionally remove tools; if backend constraints apply, extend bundle schema and handling in backend/aci/control_plane/routes/mcp_server_bundles.py to accept tool subsets.

• Additional context:

  • Consider per-config default selections and validation.