Scaffold project with Kubebuilder v4

kubebuilder init --domain ryuvia.com --repo git.ryuvia.com/niklas/terdut-operator
(--license none, no per-file header boilerplate -- terdut-server's source carries
none either). Go 1.26.0/controller-runtime v0.25.0/controller-tools v0.22.0, whatever
the current kubebuilder CLI (v4.16.0) scaffolds -- not pinned back to terdut-server's
go 1.25.9, since this is a separate module with its own toolchain.

Verified locally: build, vet, fmt all clean; `make lint` (golangci-lint, fetched into
bin/) 0 issues; `make test` (controller-gen + setup-envtest, fetched into bin/,
downloads real envtest binaries from storage.googleapis.com) passes.

Dropped kubebuilder's default .github/workflows/* -- this org runs on Gitea, not
GitHub; ci.yaml (next commit) is the only CI this repo gets.

PROJECT

@@ -0,0 +1,11 @@
+# Code generated by tool. DO NOT EDIT.
+# This file is used to track the info used to scaffold your project
+# and allow the plugins properly work.
+# More info: https://book.kubebuilder.io/reference/project-config.html
+cliVersion: 4.16.0
+domain: ryuvia.com
+layout:
+- go.kubebuilder.io/v4
+projectName: terdut-operator
+repo: git.ryuvia.com/niklas/terdut-operator
+version: "3"