wwstage dotchainresolve gated its *T roots on an N_TPTR-over-N_TNAME
tnode; an inferred `let p = alloc(S{...})!` rides the checker-
SYNTHESIZED N_TPTR whose pointee is the struct BODY node (the #24
TNAME-normalize covers only the direct struct-lit binding), so the
root gate failed and chained p.field.pseudo reads fell to the
unfused deref arms — shape-only divergence vs cstage's type-keyed
fold (both stages runtime-correct; the historical field(SB) leak the
pin described was already fixed). Widen the local and global root
gates to accept the N_TSTRUCT pointee; correctness stays enforced by
the stamped-tinfo peel below (TY_PTR -> pointee TY_STRUCT).
Graduates alias_g73_heapfill out of DATABYTEID_DIVERGED (2 pins
remain, both the tagged-spill family); adds compile fixtures pinning
the newly-converged siblings (nested read+store, slice .cap,
inferred-global root; pin 1730/22/3460) and a runtime lang row that
mutates then re-points the heap base — a read bypassing the pointer
returns the wrong len.
