Explain Terraform's moved blocks and refactoring capabilities. How do you safely rename resources, restructure modules, and migrate resources between modules without destroying and recreating infrastructure?

# Scenario 1: Simple resource rename
moved {
  from = aws_instance.web
  to   = aws_instance.application_server
}

resource "aws_instance" "application_server" {
  # Same configuration as before
  ami           = "ami-0123456789"
  instance_type = "m5.xlarge"
}

# Scenario 2: Move resource into a module
moved {
  from = aws_vpc.main
  to   = module.networking.aws_vpc.main
}

module "networking" {
  source = "./modules/networking"
}

# Scenario 3: Convert count to for_each
moved {
  from = aws_subnet.private[0]
  to   = aws_subnet.private["us-east-1a"]
}
moved {
  from = aws_subnet.private[1]
  to   = aws_subnet.private["us-east-1b"]
}
moved {
  from = aws_subnet.private[2]
  to   = aws_subnet.private["us-east-1c"]
}

resource "aws_subnet" "private" {
  for_each = toset(["us-east-1a", "us-east-1b", "us-east-1c"])
  vpc_id            = aws_vpc.main.id
  availability_zone = each.value
  cidr_block        = cidrsubnet(var.vpc_cidr, 4, index(["us-east-1a", "us-east-1b", "us-east-1c"], each.value))
}

# Scenario 4: Module rename
moved {
  from = module.old_infra
  to   = module.core_infrastructure
}

# Verify no infrastructure changes
terraform plan
# Should show:
#   # aws_instance.web has moved to aws_instance.application_server
#   # (no changes, resource address updated)