hub v0.40.0: store escrow restic_pw_sha256 + serve escrow status in the report ACK (SLICE 3)

Additive host_escrow migration; SaveHostEscrow/HostEscrow gain the hash
(NULL-safe for legacy rows); GetEscrowStatusForCustomer joins hosts;
the report ACK gains escrow:{identity_blob_present,restic_pw_sha256,
created_at} (omitted without a row). Contract test mirrors the agent's
v0.79.0 emit struct.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PSK5g6qYLknKj8u3QAFEr6

hub/internal/api/dr_test.go

@@ -71,7 +71,7 @@ func TestRestoreDirective_GatedAndExpires(t *testing.T) {
 	h, st, _ := newTestHandler(t)
 	seedHost(t, st, "h1", "c1", "HKEY")
 	// Seed a DR bundle: K-escrow row + identity blob + directive.
-	st.SaveHostEscrow("h1", []byte("opaque-K-escrow"), "01:36:e9:…", "zero_knowledge", time.Now().UTC().Format(time.RFC3339))
+	st.SaveHostEscrow("h1", []byte("opaque-K-escrow"), "01:36:e9:…", "zero_knowledge", time.Now().UTC().Format(time.RFC3339), "")
 	st.SaveHostDRBundle("h1", []byte("opaque-identity"), `{"pbs_repo":"r","tunnel_id":"t","expected_key_fingerprint":"01:36:e9:…"}`)
 
 	// Not in recovery mode → 403.

hub/internal/api/escrow_test.go

@@ -96,7 +96,7 @@ func TestHandleHostEscrow_BadBody(t *testing.T) {
 // (felhom-agent escrowUploadRequest). Cross-repo, no shared module — this is the hub half of the
 // contract guard; the agent has the mirror in its own test.
 func TestEscrowUploadContract(t *testing.T) {
-	b, _ := json.Marshal(escrowUploadRequest{BlobB64: "x", KeyFingerprint: "y", Posture: "z", CreatedAt: "t"})
+	b, _ := json.Marshal(escrowUploadRequest{BlobB64: "x", KeyFingerprint: "y", Posture: "z", CreatedAt: "t", ResticPwSHA256: "h"})
 	var m map[string]any
 	json.Unmarshal(b, &m)
 	got := make([]string, 0, len(m))
@@ -104,8 +104,75 @@ func TestEscrowUploadContract(t *testing.T) {
 		got = append(got, k)
 	}
 	sort.Strings(got)
-	want := []string{"blob_b64", "created_at", "key_fingerprint", "posture"}
+	want := []string{"blob_b64", "created_at", "key_fingerprint", "posture", "restic_pw_sha256"}
 	if !reflect.DeepEqual(got, want) {
 		t.Fatalf("escrow wire contract drift: got %v want %v (must match the agent emit struct)", got, want)
 	}
 }
+
+// SLICE 3 — the upload's restic_pw_sha256 is stored (and "" stays NULL-safe on legacy rows).
+func TestHandleHostEscrow_StoresResticPwHash(t *testing.T) {
+	h, st, _ := newTestHandler(t)
+	st.UpsertHost(&store.Host{HostID: "h1", CustomerID: "c1", APIKey: "HKEY"})
+	body, _ := json.Marshal(map[string]any{
+		"blob_b64":         base64.StdEncoding.EncodeToString(opaqueBlob),
+		"key_fingerprint":  "fp",
+		"posture":          "zero_knowledge",
+		"created_at":       "2026-07-09T20:00:00Z",
+		"restic_pw_sha256": "dbfc02f987e1ac0c91911d5761267089b1144628745a3343e4d96194e43c08e4",
+	})
+	if rr := do(h, http.MethodPut, "/hosts/h1/escrow", "HKEY", string(body)); rr.Code != http.StatusOK {
+		t.Fatalf("PUT = %d", rr.Code)
+	}
+	got, _ := st.GetHostEscrow("h1")
+	if got.ResticPwSHA256 != "dbfc02f987e1ac0c91911d5761267089b1144628745a3343e4d96194e43c08e4" {
+		t.Fatalf("hash not stored: %q", got.ResticPwSHA256)
+	}
+	// legacy upload without the field → stored empty, read back NULL-safe as ""
+	if rr := do(h, http.MethodPut, "/hosts/h1/escrow", "HKEY", escrowBody([]byte("legacy"))); rr.Code != http.StatusOK {
+		t.Fatalf("legacy PUT = %d", rr.Code)
+	}
+	got2, err := st.GetHostEscrow("h1")
+	if err != nil || got2.ResticPwSHA256 != "" {
+		t.Fatalf("legacy upload must read back with an empty hash: %q err=%v", got2.ResticPwSHA256, err)
+	}
+}
+
+// SLICE 3 — the report ACK carries the escrow status object for the customer; omitted when no escrow row.
+func TestReportACK_EscrowStatus(t *testing.T) {
+	h, st, _ := newTestHandler(t)
+	st.UpsertHost(&store.Host{HostID: "hv1", CustomerID: "cust-e", APIKey: "HK"})
+
+	// no escrow row → the ACK has NO escrow key (Scenario C: stays pending silently controller-side)
+	rr := do(h, http.MethodPost, "/report", globalKey, `{"customer_id":"cust-e"}`)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("report = %d", rr.Code)
+	}
+	var ack map[string]any
+	json.Unmarshal(rr.Body.Bytes(), &ack)
+	if _, present := ack["escrow"]; present {
+		t.Fatal("no escrow row → the ACK must omit the escrow object")
+	}
+
+	// escrow row with identity blob + hash → the ACK carries all three fields
+	if err := st.SaveHostEscrow("hv1", []byte("k-blob"), "fp", "zero_knowledge", "2026-07-09T20:00:00Z", "abc123"); err != nil {
+		t.Fatal(err)
+	}
+	if err := st.SaveHostDRBundle("hv1", []byte("identity-blob"), "{}"); err != nil {
+		t.Fatal(err)
+	}
+	rr2 := do(h, http.MethodPost, "/report", globalKey, `{"customer_id":"cust-e"}`)
+	var ack2 struct {
+		Escrow struct {
+			IdentityBlobPresent bool   `json:"identity_blob_present"`
+			ResticPwSHA256      string `json:"restic_pw_sha256"`
+			CreatedAt           string `json:"created_at"`
+		} `json:"escrow"`
+	}
+	if err := json.Unmarshal(rr2.Body.Bytes(), &ack2); err != nil {
+		t.Fatal(err)
+	}
+	if !ack2.Escrow.IdentityBlobPresent || ack2.Escrow.ResticPwSHA256 != "abc123" || ack2.Escrow.CreatedAt == "" {
+		t.Fatalf("ACK escrow status wrong: %+v (body=%s)", ack2.Escrow, rr2.Body.String())
+	}
+}

hub/internal/api/handler.go

@@ -334,6 +334,14 @@ func (h *Handler) handleReport(w http.ResponseWriter, r *http.Request) {
 		resp["config_version"] = custCfg.ConfigVersion
 	}
 
+	// SLICE 3 — escrow status for the hub-verified auto-confirm: the controller flips its offbox
+	// EscrowState pending→escrowed ONLY when sha256(its local repo password) matches restic_pw_sha256
+	// (blob-presence alone must never confirm — a stale blob may not cover the current key). The hash is
+	// non-reversible (256-bit random secret) — safe to serve; omitted entirely when no escrow row exists.
+	if es, err := h.store.GetEscrowStatusForCustomer(payload.CustomerID); err == nil && es != nil {
+		resp["escrow"] = es
+	}
+
 	// Phase 2 managed updates: advertise the effective controller-version FLOOR (per-customer override
 	// else global default) and the latest available version. The controller compares its current
 	// version against the floor and auto-updates when below it (latest stays the customer's opt-in
@@ -828,6 +836,9 @@ type escrowUploadRequest struct {
 	// Slice 10D.1 — optional DR bundle, stored alongside the K-escrow (both opaque/non-secret).
 	IdentityBlobB64 string          `json:"identity_blob_b64,omitempty"` // age-wrapped {tunnel_token, pbs_token}
 	DirectiveJSON   json.RawMessage `json:"directive,omitempty"`         // non-secret directive (pbs repo/ns, expected fp, tunnel id)
+	// SLICE 3 — sha256 hex of the restic repo password sealed in the identity blob (non-reversible hash
+	// of a 256-bit random secret — safe to store/serve; present only when a staged password was folded in).
+	ResticPwSHA256 string `json:"restic_pw_sha256,omitempty"`
 }
 
 // handleHostEscrowPut stores a host's opaque escrow blob (doc 03 §8a). Authed with the PER-HOST key
@@ -868,7 +879,7 @@ func (h *Handler) handleHostEscrowPut(w http.ResponseWriter, r *http.Request, pa
 		createdAt = time.Now().UTC().Format(time.RFC3339)
 	}
 	// Store the OPAQUE bytes. No decrypt path exists — the hub cannot open this.
-	if err := h.store.SaveHostEscrow(pathHostID, blob, req.KeyFingerprint, req.Posture, createdAt); err != nil {
+	if err := h.store.SaveHostEscrow(pathHostID, blob, req.KeyFingerprint, req.Posture, createdAt, req.ResticPwSHA256); err != nil {
 		h.logger.Printf("[ERROR] Failed to store escrow for host %s: %v", pathHostID, err)
 		http.Error(w, "Internal error", http.StatusInternalServerError)
 		return