(** The session worker: process the stale markers once. *)

type outcome = { built : string list; failed : string list }

val log : Switch.t -> string -> unit
(** Append a timestamped line to the switch's odd log. Best-effort; never
    raises. *)

val sync : ?driver:Bos.Cmd.t -> Switch.t -> (outcome, [ `Msg of string ]) result
(** Rebuild every package with a stale marker ({!Pending}), in dependency order,
    each erased then rebuilt via the driver (default [odd-driver]), and
    regenerate the landing page. A successful build clears the marker (the erase
    removes it); a failed one re-marks the package so the next session retries.
    Removals are not handled here — the post-remove hook deletes the docs
    directly — but the landing page is regenerated every session so removed
    packages drop off it. Runs under a lock file; driver output goes to the
    log. *)

val summary : outcome -> string
(** One line, e.g. ["2 built, 0 failed"]. *)