#4203 Docs: working offline against swamp serve (leases, outbox, flush, quarantine) for swamp-club#4195

swamp-club#4195 (datastore rework Phase 5, team mode) lets a serve-mode checkout keep working while serve is unreachable. The manual needs to explain it.

What changes for users

• Offline, reads and read/list methods keep working from the local copy (with a staleness warning).
• A method that changes things runs offline only on a behavior whose lease was checked out while online: swamp behavior lease acquire <name> --for <duration>, now up to 24 h. Without one the run is refused (datastore_v3_offline_lease_required, exit 75). Definition edits are refused offline.
• Offline work is saved in the local outbox and the command exits 0. The next command that reaches serve sends it.
• On reconnect, offline versions are renumbered after versions written meanwhile. latest follows when the work was observed: an offline write becomes latest only when more than 5 minutes newer than the current latest; otherwise the current latest is restated as a new highest version.
• A write whose grant was revoked while offline is quarantined, shown by swamp datastore status, and an admin can accept it with swamp datastore quarantine accept <txnId>.
• Explicit leases survive a serve leader takeover. An admin can end an abandoned lease with swamp datastore lock release --force --behavior <name>.

Pages

• content/manual/reference/datastore-configuration.md and content/manual/reference/swamp-serve.md: offline rules, outbox states, exit codes, the 24 h lease bound.
• content/manual/how-to/collaborate.md (or a new how-to "Work offline against swamp serve"): check out a lease, work offline, reconnect, read the flush report.
• content/manual/reference/data.md: what latest means after a rebase, the _swamp.restates tag.

Write after swamp-club#4195 merges.