ip-algo: pod annotation > NodeConfig annotation > random

Add flock.fritzlab.net/ip-algo as a node-wide default via NodeConfig
metadata.annotations. Pod-level annotation still wins. Empty, missing,
or invalid input at either level falls through to the next; invalid
values warn-log via the agent's slog. Both unset → fully random IID
(unchanged baseline).

ParseAnnotations no longer touches ip-algo; ResolveIPAlgo handles the
full precedence chain, called from PodHandler.Add with the cached
NodeConfig's annotations and the agent logger.

Tests: 9 new TestResolveIPAlgo_* cases covering pod-wins, all
fall-through paths, both-absent, nil node map, whitespace, and
duplicate-as-invalid. Fuzz target rebuilt without ip-algo input space
(now exercised by ResolveIPAlgo unit tests).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pkg/agent/runtime_linux.go

@@ -149,6 +149,7 @@ func (s *Server) configureRuntime(ctx context.Context) error {
 		IPAM:         ipam,
 		Pods:         pods,
 		NodeConfig:   s.NodeConfig,
+		Logger:       s.Logger,
 		SetupFunc:    Setup,
 		TeardownFunc: Teardown,
 		AfterCommit: func() {