Extends 1036-errors-failable-smoke with an end-to-end Composition section
covering the E5.1 forms: a failable closure literal through a Closure(...)
param (try-propagated, caught), a non-failable closure literal widened
into a failable bare slot (∅-widening adapter), and generic ($T)
value-carrying failable composition. Completes E5.4 — the per-feature
examples (1039-1045) remain the focused units; this is the integrated
smoke.
Break the monolithic examples/50-smoke.sx into 30 focused per-section examples,
filed into their category blocks (basic/types/comptime/memory/protocols/ffi),
each carrying only the top-level decls its section references (the protocols
section keeps the full preamble — its deps flow through UFCS method calls that
name-based extraction can't see). Outputs verified identical to the original
section blocks.
Add examples/1036-errors-failable-smoke.sx — an end-to-end error-handling example
(the E5.4 work): named + inferred error sets consumed via destructure, try (in
helpers), catch (bare-expr / match-body / diverging / no-binding), or
value-terminator, onfail+defer interleave, and error.X value + {} tag
interpolation.
Remove examples/50-smoke.sx. Suite: 324 passed, 0 failed.
