Implements the 2026-09-09 fleet-id-order resolution, section 3 item 1. Given the
pre-turn save, compute the ids new in each post-turn save, match the client-minted
(node nibble != 0) new fleets by a key that does not mention the id -- (LocID or
FPlan destination, sorted ship-id set) -- build the bijection pi, rewrite every
fleet reference, compare the master id lists as sets, mask /Summary/Checksum with
its reason on the line, and print pi.
Acceptance, both halves:
bp-pinA vs bp-pinB IDENTICAL modulo pi = {1970<->1986} (35 leaves -> 0)
ad-oracle-A vs -B REFUSED, then DIVERGED: 94 leaves (unchanged)
Five guards, every one refusing rather than degrading: only ids absent from the
pre-turn save; only non-zero node nibbles; pi must permute one set; content keys
must correspond one-to-one and be unique per side; and no leaf anywhere may hold a
permuted id at an unmodelled site (matched on raw bytes, not the reader's typed
value). A refusal rewrites nothing and falls back to the ordinary comparison.
Three corrections to the specification from contact with the data, in
findings/subsystems/relabel-new-ids.md section 4: FtName is an id-attached label
and needs the same treatment as the id; relabelling the Flt[] keys is the wrong
operation (exchange the bodies -- the fleet table is id-ordered and identical in
both saves); a node's new-id set spans object kinds.
Default path proven unchanged: pre- and post-change modules agree on the root
digest, coverage, mask hits and every (path, digest) in the tree over all 43 saves
under two policies, and on 5,602 lines of CLI stdout across every mode.
Also fixes a pre-existing, unrelated test failure: the re-save localisation test
enumerated pairs over sorted filenames and hard-coded the direction 4 -> 0, which
a later corpus addition reversed. Suite 38 -> 62 tests, all passing.