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).
246883073c