hub v0.7.2: ingest agent storage_targets (slice 5 Phase A)

Accept + persist the now-populated host-report storage_targets. Minimal — the
authoritative storage manifest is hub-owned (slice 10); this mirrors what the agent
observes.

- hostReportPayload.StorageTargets: full mirror of the agent's hub.StorageTarget
  wire contract; persisted verbatim in report_json (no schema change); count +
  WARN on disconnected targets.
- shared host-report golden updated with two populated targets; byte-identical with
  felhom-agent's copy.
- TestHostStorageTarget_GoldenContract: hub half of the bidirectional key-set test.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

hub/internal/api/handler.go

@@ -234,9 +234,15 @@ const defaultHostPollSeconds = 900
 const maxHostReportBytes = 4 << 20 // 4 MiB
 
 // hostReportPayload is the subset of the agent host-report (slice-3 contract,
-// §3 / agent spec §4) the hub needs for denorm + guest reality. Unknown fields
-// (storage_targets/backups/restore_tests/pbs_snapshots/audit_tail) are ignored,
-// so an empty or absent collection is accepted without error.
+// §3 / agent spec §4) the hub needs for denorm + guest reality. The remaining fields
+// (backups/restore_tests/pbs_snapshots/audit_tail) are ignored, so an empty or absent
+// collection is accepted without error.
+//
+// storage_targets (slice 5) is now parsed: the agent populates it, and the hub accepts
+// + persists it. Persistence is the full report_json row (which carries the targets
+// verbatim) plus the denorm counts below — the RICH manifest schema (desired class/role/
+// policy/creds) is hub-owned and lands in slice 10; this slice only mirrors what the agent
+// observes.
 type hostReportPayload struct {
 	HostID       string `json:"host_id"`
 	AgentVersion string `json:"agent_version"`
@@ -251,11 +257,49 @@ type hostReportPayload struct {
 		Status            string `json:"status"`
 		ControllerVersion string `json:"controller_version"`
 	} `json:"guests"`
-	Cloudflared struct {
+	StorageTargets []hostStorageTarget `json:"storage_targets"`
+	Cloudflared    struct {
 		Status string `json:"status"`
 	} `json:"cloudflared"`
 }
 
+// hostStorageTarget mirrors the agent's hub.StorageTarget wire contract field-for-field.
+// It is a DUPLICATED contract (no shared types module yet); testdata/host-report.golden.json
+// must stay byte-identical with felhom-agent's copy and the key-set test guards drift.
+// The hub does not act on these yet beyond persisting + counting them (slice 10 adds the
+// authoritative manifest), but mirroring the full shape keeps the cross-repo contract honest.
+type hostStorageTarget struct {
+	Name          string  `json:"name"`
+	Type          string  `json:"type"`
+	DurableID     string  `json:"durable_id"`
+	State         string  `json:"state"`
+	Reachable     bool    `json:"reachable"`
+	TotalBytes    int64   `json:"total_bytes"`
+	UsedBytes     int64   `json:"used_bytes"`
+	AvailBytes    int64   `json:"avail_bytes"`
+	UsedFraction  float64 `json:"used_fraction"`
+	Content       string  `json:"content"`
+	MountPath     string  `json:"mount_path"`
+	BackingDevice string  `json:"backing_device"`
+	ClassHint     string  `json:"class_hint"`
+	Role          string  `json:"role"`
+	ThinPool      *struct {
+		DataUsedFraction     float64  `json:"data_used_fraction"`
+		MetadataUsedFraction *float64 `json:"metadata_used_fraction"`
+	} `json:"thin_pool,omitempty"`
+	Smart struct {
+		Health               string `json:"health"`
+		TemperatureC         *int   `json:"temperature_c"`
+		PowerOnHours         *int   `json:"power_on_hours"`
+		ReallocatedSectors   *int   `json:"reallocated_sectors"`
+		PendingSectors       *int   `json:"pending_sectors"`
+		OfflineUncorrectable *int   `json:"offline_uncorrectable"`
+		CriticalWarning      *int   `json:"critical_warning"`
+		MediaErrors          *int   `json:"media_errors"`
+		PercentageUsed       *int   `json:"percentage_used"`
+	} `json:"smart"`
+}
+
 // handleHostReport ingests the agent's host-report (the heartbeat) and returns the
 // control envelope (agent spec §5).
 func (h *Handler) handleHostReport(w http.ResponseWriter, r *http.Request) {
@@ -340,7 +384,22 @@ func (h *Handler) handleHostReport(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	h.logger.Printf("[INFO] host-report from %s (%d guests, %d bytes)", hostID, len(rep.Guests), len(body))
+	// storage_targets (slice 5): persisted as part of report_json above. Count + surface
+	// disconnected ones in the log (the slice-10 manifest will reconcile them; for now the
+	// signal is the visibility — a disconnected target is the storage analog of host-down).
+	disconnected := 0
+	for _, st := range rep.StorageTargets {
+		if st.State == "disconnected" {
+			disconnected++
+		}
+	}
+	if disconnected > 0 {
+		h.logger.Printf("[WARN] host %s reports %d disconnected storage target(s) of %d",
+			hostID, disconnected, len(rep.StorageTargets))
+	}
+
+	h.logger.Printf("[INFO] host-report from %s (%d guests, %d storage targets, %d bytes)",
+		hostID, len(rep.Guests), len(rep.StorageTargets), len(body))
 
 	blocked := false
 	if cc, err := h.store.GetCustomerConfig(custID); err == nil && cc != nil && cc.Status == "blocked" {