ABBREVIATION-LEGALITY VERDICT for an ANCHORED, PRE-LOCALISE alias body (shared by
 the Transient and Concrete alias arms — the check must see atoms, and localise
 widgetizes them). Two F#-illegal abbreviation shapes degrade, LEDGERED:
  (1) SELF-REFERENCE — a body atom carrying the alias's OWN path is the prerender
      cycle-break placeholder (`type X<'T> = option>`, conditional-alias
      chains whose branches resolve back through the alias node): cyclic garbage
      by construction (FS0953).
  (2) PHANTOM TYPARS — a declared typar absent from the (post-scrub) body makes
      the abbreviation illegal (FS0035), and the arity-CHANGING fix needs every
      ref-arity source coordinated (the pinned +196 regression).
 `Some localisedBody` = legal abbreviation; `None` = the caller must emit the
 erased-preamble shape instead (an EMPTY INTERFACE with the same name and arity —
 refs stay legal at every use site, the unexpressible body becomes an opaque token).

 `anchorScrubLocalise` with the ANCHOR and LOCALISE roles SPLIT (the module-global
 holder classes — the Variable-arm rpcStub fix extended to Function params/returns):
 transient atoms resolve against the export's TRUE anchor, the same anchor the def
 walk places hoisted literals with, so a param literal's ref and def agree by
 construction (nameless ↔ nameless, Case{n} ↔ Case{n}); localisation shortens
 against the holder's REAL emission scope (namespace root), keeping the full
 module qualification. One shared anchor breaks one side or the other (the
 PartyServer GetServerByName class).

 The SCRUB HOST is the caller's choice, per channel history:
  - PARAMS pass the LOCALISE anchor — its legacy empty module trace indexes as
    unit 1, degrading holder-function param refs to obj as they always have been.
    Correcting their host to the export's unit (measured) lets REAL refs through,
    most valid — but cross-owner cache-hit literals whose defs materialized at
    their FIRST owner's path then dangle (Workers: the ExportedHandler.Fetch
    cf-properties literal referenced from the fetch holder as bare
    CloudflareWorkersTypes.Fetch). Params' host correction lands TOGETHER with
    the cross-owner def/ref closure, not before.
  - VARIABLE typeRefs and FUNCTION returns pass the RESOLVE anchor (the correct
    host): these channels were NEVER scrubbed, so there is no legacy to preserve
    and scrubbing only ADDS degradations — it cannot surface new refs. Their
    unscrubbed state was the Mcp first-count channel gap (obj-with-args escaping
    the collapse; the Mcp->Agents stray back-edges escaping the forward-DAG scrub).