Surface rename of the signed integer family: s1..s64 become i1..i64
(u1..u64, usize, isize unchanged). 'string' keeps the s-prefix arm in
name classification; width parsing moves to the i-prefix arm next to
isize.
Internal TypeId tags follow the surface (.s8/.s16/.s32/.s64 ->
.i8/.i16/.i32/.i64), as do mono-key mangle fragments (ptr_i64,
tu_i64_bool) and all display/diagnostic formatting (i{d}).
Migrated in the same sweep: stdlib + examples + issue repros + FFI C
companions (shared symbol names like ffi_id_i64), expected
stdout/stderr/ir snapshots, specs.md, readme.md, CLAUDE.md/AGENTS.md,
implementation_plan.md, docs/, issue writeups. Vendored stb_image and
historical flow state left untouched.
zig build test: 426/426; examples suite: 595/595.
attempt-1's per-decl enum/union register path panicked on any valid
self- or mutually-referential top-level enum/union: a `*Name` field in
the body is resolved through the stateless `type_resolver.resolveNamed`,
which has no kind context and forward-stubs an as-yet-unregistered name
as a STRUCT. `internNamedTypeDecl` then `findByName`-adopted that struct
stub and called `updatePreservingKey`, whose kind-stability assert tripped
on struct -> enum/union (types.zig:446). The corpus had no recursive
enum/union, so the gate missed it.
Fix: when the slot `findByName` returns is a wrong-kind forward struct
placeholder (empty-fields struct) for an enum/union/tagged_union
registration, re-key it in place (`replaceKeyedInfo`) under the same
TypeId instead of `updatePreservingKey`. This mirrors how a self-ref
struct adopts its own (same-kind) forward stub; the new helper
`adoptsForwardStructStub` gates the re-key precisely to that case, so a
struct adopting a struct stub and every non-recursive enum/union stay on
the byte-identical `updatePreservingKey`/fresh-intern path.
Regression 0799 (single-author): self-ref union linked cells
(`next: *Node`), self-ref enum/tagged-union (`branch: *Tree`), and a
mutual-ref pair (A holds *B, B holds *A); builds and walks each recursive
link. Fail-before: panic at registerUnionDecl on eed2f99. Pass-after:
exit 0, "union=7 enum=42 mutual=99".
Gate: zig build && zig build test && run_examples.sh all exit 0
(538 passed, 0 failed; 0795-0798 + 0752-0794 + FFI byte-identical);
m3te ios-sim build via the main binary exit 0.
