flock M1 scaffold: CNI plugin + agent + NodeConfig CRD

- cmd/flock + cmd/flock-agent: build cleanly; CNI ADD/DEL/CHECK return
  ErrInternal stubs until M2; agent boots, opens unix socket, logs JSON.
- pkg/agent/state.go: durable allocations.json (atomic write + fsync +
  parent fsync); pending/committed lifecycle. Tests cover round-trip,
  replace-by-cid, version mismatch, no-leak-on-tmp.
- pkg/embed/suffix.go: ip-algo IID embedding. Tests cover the /48-/96
  nibble distribution table from the design doc, determinism, prefix
  preservation, N-nibble isolation, digest-vs-fallback divergence.
- pkg/api/v1alpha1: minimal NodeConfig types (no controller-runtime yet).
- deploy/: NodeConfig CRD, empty ServiceAccount/ClusterRole, DaemonSet
  pinned to flock.fritzlab.net/agent="" label so it only runs on opted-in
  nodes.
- .gitea/workflows/main.yaml + Dockerfile: build + push to
  code.fritzlab.net/fritzlab/flock; runs go test in CI.

Design doc: dfritzlab/k8s-manager/dfritz-cni.md.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -0,0 +1,22 @@
+# flock
+
+Kubernetes CNI for sjc001. Per-pod IPv4 opt-in, IID embedding, Ready-gated anycast via BGP.
+
+Design doc: `k8s-manager/dfritz-cni.md` (in the operator's k8s-manager repo).
+
+Status: M1 scaffold. Not functional. See milestones table in the design doc.
+
+## Layout
+
+- `cmd/flock` — CNI plugin binary (kubelet-invoked)
+- `cmd/flock-agent` — DaemonSet binary
+- `pkg/api/v1alpha1` — `NodeConfig` CRD types
+- `pkg/cni` — CNI plugin internals + RPC client
+- `pkg/agent` — agent server, IPAM, state file, anycast, NetworkPolicy
+- `pkg/embed` — `ip-algo` IID embedding (pure)
+- `pkg/routing/{bird,ospf}` — routing backends
+- `deploy/` — CRDs, RBAC, DaemonSet manifests
+
+## License
+
+Apache 2.0.