wwstage's parsef64 (naive i64-accumulator + pow-10 fold) diverged from
cstage's strtod: >19-digit mantissas overflowed the accumulator (sign-bit
garbage), DBL_MIN was +1 ULP, DBL_MAX -2 ULP — the #59.10 ratchet pin.
C-strtod oracle confirms cstage correctly rounded on every vector, so
wwstage aligns to it by dogfooding strconv.stof64 (correctly-rounded
decimal engine, already imported by lex.ww). Overflow literals now
reject in both stages (stof64 overflow -> errat, mirroring ERANGE).
Fix + #59.10 M_DIVERGE->M_ID graduation + pins land together per the
ratchet's designed flow (the gate trips loud demanding graduation):
oracle-pinned vectors in toktest.ww floatfold_cases (lexer-unit) and
989_floatlit_run (compiler fold: runtime bits + byte-id + overflow
reject parity). Retained subnormal accept-set asymmetry filed as task
#21, documented at the lexnum site.
