Go does not distinguish bootstrap observers from unit tests: an
in-process test is a unit test. 738 is pure parsefile calls (arena +
lexinit + parserinit, AST assertions, zero subprocess or artifact
claims) — the 200_parse class, misfiled among the residuals. The
fleet partition now reads six units / six bootstrap / three platform
and the residual class is empty; COMPILER_WRAPPER_SOURCES drops it
by the existing filter-out. Doc roster updated (also refreshes the
corpus prose to the current 1745/3490 pin and retires the stale
794-era paragraph).