`forge-avatar-sync.path` used `PathExists=`. systemd.path(5): a
`PathExists=` condition that already holds activates the configured unit
immediately whenever the path unit is activated. A `Type=oneshot` unit
with `RemainAfterExit=false` deactivates after each run, which re-arms
the path, which fires again because the token is still there — an
unconditional loop that ends at `StartLimitBurst`.
Measured on a container boot carrying the previous fix: five starts and
`start-limit-hit` with the glob already removed and exactly one matching
file. So the count was never one-per-token; it was the start limit, and
scoping the watch (#4025) could not have fixed it.
`PathChanged=` does not fire on an already-present path, and hive-priv
writes this file in place — `write_state_file_nofollow` opens with
`O_TRUNC` and no rename — so close-after-write still triggers it. The
token-present-at-boot case stays covered by the service's own
`wantedBy = multi-user.target`.
Same directive and same reasoning as `swarm-controller.nix`'s
queue-credential watcher, which reached it first: "`PathChanged=` requires
a write, so it cannot do that and cannot spin."
The comment claiming the storm came from many agents' tokens arriving at
once is removed with it — that model is what let the defect survive the
previous fix.
Refs #3984.
e9faa3896f