fix(controller): accept legacy manifest flags

[5park1e]

Summary

• extract controller flag registration into a testable options binder in cmd/controller/options.go
• keep accepting kube client rate-limit flags used by older manifests
• accept the legacy --v flag from early controller Helm charts and log a deprecation message
• add unit coverage for legacy controller manifest argument sets in cmd/controller/options_test.go

Validation

• docker run --rm -u 1000:1000 -v /home/zhanghaojie/code/OpenSandbox/kubernetes:/workspace -v /tmp/opensandbox-go-build:/tmp/go-build -v /tmp/opensandbox-go-mod:/tmp/go-mod -w /workspace -e GOCACHE=/tmp/go-build -e GOMODCACHE=/tmp/go-mod golang:1.24 bash -lc '/usr/local/go/bin/gofmt -w cmd/controller/main.go cmd/controller/options.go cmd/controller/options_test.go && /usr/local/go/bin/go test ./cmd/controller'

Fixes #855

[CLAassistant]

All committers have signed the CLA.

[5park1e]

This PR touches the Kubernetes controller compatibility path. Could a maintainer please add the component/k8s label?

[5park1e]

Thanks for the suggestion. I moved the controller options binding logic out of main.go and kept the coverage in options_test.go, so the test now targets the extracted options layer instead of main.go directly.