feat: bounded node delegation renewal

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## [Unreleased]
 ### Changes
+- Delegation renewal uses owner-signed, exact-CID leases and signed bounded renewal stamps. Lease revocation immediately ends renewed access.
 - Encryption: v2 column format with key ids, per-purpose keys and recorded format metadata. Optional strict reads are off by default. Details: TC-2516, TC-2517.
 - Encryption network key-wrap v1 uses the explicit legacy column codec after the TC-2516 integration; wire bytes and default-off v2 writer flags are unchanged. Details: TC-2518.
 - Deploys: the workflow supports an explicit, reason-recorded rollback to an earlier released dstack image on the unchanged N0 compose. It checks image labels, release tag, ancestry, and identical migration sources while preserving the normal forward-release guard.

docs/runbooks/renewal-leases.md

@@ -0,0 +1,9 @@
+# Renewal lease operations
+
+This runtime slice supports owner-signed lease registration, node-internal scheduled renewal, the existing revocation flow, and read-only status. There is no external renewal trigger or route: the node scheduler signs renewals with its dedicated renewer key, which is never returned to clients. External clients register owner-signed leases and read status.
+
+Stopping and re-enabling a lease are deferred to a later slice. Until then, the owner's only off switch is revocation, which is irreversible.
+
+The node persists a monotonic renewer epoch beginning at 1. A lease and its stamps are usable only while both the lease's renewer DID and epoch match the node's current identity. If a KMS key change produces a new renewer DID, old leases and their stamps stop extending grants; owners must register new leases. This is an availability consequence, not a security failure.
+
+A database restore can roll the persisted epoch back. An old-epoch lease could become usable again only if the old renewer key also returns, producing the matching DID and epoch. Keep the restored database and node key state consistent; do not treat a database restore alone as revocation.

tinycloud-core/Cargo.toml

@@ -33,6 +33,8 @@ async-std = [
 
 [dependencies]
 dashmap = "5.5"
+blake3 = "1"
+ed25519-dalek = { version = "2", default-features = false, features = ["std"] }
 async-trait.workspace = true
 sea-orm = { version = "1.1", default-features = false, features = ["macros", "with-time", "with-json", "postgres-array"] }
 sea-orm-migration = { version = "1.1", default-features = false }