fix(pm): read-back judge collapses the read path's own-repo reference expansion before calling a body mutated

A proxied REST read in a cloud seat container intermittently spells a bare
`#N` as `owner/repo#N`. The stored bytes are unchanged, but classifyReadBack
compared them byte-exact and answered `mutated` (exit 4 / relay `not-stored`),
whose remedy sends a seat to re-send the expanded body.

Before `mutated`, the judge now walks sent and stored in step and, only where
the sent body opens a bare reference, allows one of the fleet roster's slugs
in front of that `#` (one slug per body). If the collapsed body is one of the
declared classes, the verdict is the new landed class
`reference-expanded-on-read` with `afterCollapse`, `referenceExpanded` and
`referencePrefix`; otherwise it stays `mutated`, with the offset taken after
the collapse. post-stamped prints one stderr line naming the count on both
output shapes, `--json` carries the fields, and the NOT STORED text warns
against re-sending an expanded read. classifyReadBack's signature is
unchanged, so fleet-write/dispatch.mjs's imported judge and its content-based
comment lookup take the collapse with no edit there.

Claude-Session: https://claude.ai/code/session_01HEdP5tPhqQfzwRmKDxwn85
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude