The new escrow package reaches the hub only when its code is claimed (R-978, unreleased)

The root ceremony uploaded the new package before the new code was claimed, and the hub
overwrites the current package when the sealed secrets are unchanged: a customer who started the
ceremony again and walked away kept a written-down code that opened nothing. Json mode (the
FELHOM_ESCROW argv, unchanged) now returns the package (CeremonyOutput v2, PendingUpload); the
daemon uploads it at POST /escrow/ceremony/claim before handing out the code. A failed upload is a
502 with the code still claimable; TTL and a new start wait for an in-flight claim upload; no
uploader is a 503. Text mode still uploads at once. No sudoers change.
Tests TestEscrowCeremony_R978_* (localapi) and the cmd-side defer/delivery/wiring tests, red-proved.

internal/escrow/ceremony.go

@@ -1,5 +1,7 @@
 package escrow
 
+import "encoding/json"
+
 // Controller-driven ceremony contract (v0.88.0, TASK 2026-07-13; mechanics validated by
 // felhom.eu/documentation/audits/SPIKE-controller-escrow-2026-07-13.md). The agent's local API
 // re-invokes the agent binary as root via `sudo -n` with ONE fixed argument vector; sudoers
@@ -43,7 +45,15 @@ type CeremonyOutput struct {
 	IdentityBlobBytes int     `json:"identity_blob_bytes"`
 	ResticPwSealed    bool    `json:"restic_pw_sealed"`
 	Uploaded          bool    `json:"uploaded"`
+	// PendingUpload (version 2, R-978) is the hub upload body — the R-wrapped blobs (ciphertext), the key
+	// fingerprint and the sealed password's hash — that json mode hands back INSTEAD of uploading. The agent
+	// daemon uploads it only when the customer claims the new recovery code, so a ceremony that is started
+	// and abandoned never replaces the package the customer's previous code opens. Not a secret without R,
+	// but never logged. Uploaded is false whenever this is set.
+	PendingUpload json.RawMessage `json:"pending_upload,omitempty"`
 }
 
-// CeremonyOutputVersion is the current CeremonyOutput.Version value.
-const CeremonyOutputVersion = 1
+// CeremonyOutputVersion is the current CeremonyOutput.Version value. 2 (R-978): json mode no longer
+// uploads; it returns PendingUpload. The daemon refuses any other version (a binary/daemon mismatch
+// fails the ceremony instead of losing a package).
+const CeremonyOutputVersion = 2