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.
E4 non-transitive type rule had two generic-head author-selection holes:
#1 A BARE generic struct head / alias with a single bare-VISIBLE author still
instantiated a NON-visible 2-flat-hop same-name template, because the
`.unregistered` gate arm fell through to the global last-wins
`struct_template_map` winner. Add `bareVisibleStructTemplate`: after the
visibility gate passes, select the source-keyed template authored by the
single bare-visible author (own-wins, else the one 1-hop flat author) and
instantiate THAT instead of the global map's last-wins entry. Null (→ the
global map, byte-identical) when the visible author IS the canonical one
(the common single-author case) or the picture isn't a clean single author.
Applied at every bare generic-struct head/alias site (annotation `.call` /
`.parameterized_type_expr`, alias-registration `.call` /
`.parameterized_type_expr`, array-literal head).
#2 A QUALIFIED head `a.Box(..)` whose namespace `a` authors no member `Box`
silently fell back to the bare global template, instantiating an unrelated
module's `Box`. Add `qualifiedMemberMissing`: a qualified head whose known
namespace lacks the member now emits "namespace 'a' has no member 'Box'" and
poisons with `.unresolved`; a qualified head NEVER reaches the bare global map.
Regressions: 0774 (bare head + bare alias, 2-hop same-name → size=8 alias=8,
fail-before 16 16); 0775 (qualified missing member → diagnostic + exit 1,
fail-before size=16 exit 0).
