The fleet half of R-39. An ep0 credential re-issue re-keys the SECRET of an existing
token, so token_id, fingerprint, datastore and namespace all come back byte-identical.
The agent re-applies on the descriptor's CONTENT HASH, so a re-issue was invisible to a
converged box: it short-circuited, never consumed the fresh secret, and served a revoked
credential while reporting `applied` — the N100 failure of 2026-07-18.
host_pbs_secrets gains a monotonic per-host `generation`, advanced by every fresh MINT and
by nothing else, stamped into the descriptor as `secret_generation`. That is now the only
field a re-key moves, and it is what re-arms the agent.
DEVIATION FROM SPEC, deliberate: the brief said to return "the new row's id (int64) …
no schema change". There is no row id — host_pbs_secrets is keyed by host_id and UPSERTed
last-write-wins, so a new row never exists, and created_at collides for two mints in the
same second. An additive counter column is the only monotonic source; it uses the repo's
existing idempotent ALTER-TABLE idiom.
RestageHostPBSSecret deliberately does NOT advance it: a re-stage re-arms the SAME secret,
the descriptor content genuinely has not changed, and a bump would cause a pointless agent
refetch loop (that method's own contract says so).
Also corrects a comment that asserted the re-issue refreshes the descriptor "with the NEW
token_id/fingerprint". That is false for a re-key, and believing it is why the descriptor
was never expected to be identical in the first place.
omitempty is load-bearing: a zero generation must not start emitting a new key into every
pre-existing descriptor, which would itself be a fleet-wide spurious re-apply.
Compatibility: agents below 0.91.0 drop the unknown JSON key and behave exactly as today —
inert, not breaking (Scenario C).
Tests: store-level monotonicity + per-host isolation + restage-leaves-it-alone; descriptor
byte-change, omitempty, and sibling-key round-trip; and a FLOW-level test driving
ReissuePBSDR against a fake that models a real re-key. Red-proof run at the assertion
level (not the compiler): commenting out the stamp makes the flow test fail with both
byte-identical blocks printed.