Flip the soft-default to a hard "missing package clause" error symmetrically in
both stages (cmd/wcc/parse.c + lib/ww/syntax/parse.ww): the first real decl of a
primary section with empty pathmod/resetmod and no seen clause is now rejected.
Closes the documented soft-default divergence (the 63-wrapper carve-out).
The gate flip can't be split from the migration it breaks, so this is one atomic
commit: ~80 test/wcc wrappers gain `package main;` via a shared wwtestpkg.h
helper, 6 data fixtures plus 17 asm-grep assertions update for the bare->main.<leaf>
root-helper mangle shift, and rt/ declares `package rt;` with @symbol pinning the
bare rt_ensure/rt_malloc linker names.
Root mangling narrows: the executable entry `main` stays bare (existing
carve-out), but root helper symbols become main.X. The #84 cluster is rewritten
to assert main.run distinct from aa.run/test.run; its cgen fix and bare machinery
are retained — still load-bearing for package-less module-reset deps. New
table-driven test 782_strict_package.c (6 rows, both stages).
Retiring //ww:module-reset is deferred to #24b: it is load-bearing (clears the
.wwi pathmod so the body's package clause asserts), not a vestige; fusing its
removal here would be a silent mismatch.
All byte-id gates green; full make test reports "all 335 tests passed".
cstage variadic gather stored only AX (.ptr) per element; .len and
.cap read stack residue at the callee. Tagged-union variadic path
escaped because cg_widen_tagged_store wrote the full slot — but
primitive-type variadics (str..., slice...) silently dropped the
trailing fields. Selfhost only uses tagged-union variadics
(formattable...) so bootstrap byte-id ww2==ww3==ww4 stayed green;
the bug surfaced in worker-strings pre-flight (session 5) on the
Hare-faithful concat(strs: str...) shape.
Per-element store branch now mirrors selfhost/cmd/wcc/cgenexpr.ww
velemstr (AX→slot+0, BX→slot+8) and velemslice (AX→slot+0,
BX→slot+8, CX→slot+16). Also swap dname-before-sname allocation
order in the variadic-pack frame layout to match wwstage scanlocals
+ localadd order (cgendecl.ww:507-516 and cgenexpr.ww:2949-2954);
without the swap post-fix asm has correct stores at mismatched
offsets vs wwstage.
Rule-10 alignment: cstage UP to wwstage's already-correct primitive
variadic path.
743_variadic_pack pins the contract: asm-presence ≥3 ptr-stores +
≥3 len-stores in caller TEXT on both stages, plus cs-vs-ws cmp -s
byte-id per row. 117/117 ok. Bootstrap byte-id ww2==ww3==ww4 holds.
Unblocks: lib/bytes contains-variadic, lib/strings sub variadic,
and the concat/trim/contains family that c1 shipped non-variadic.
