Complete C implementation of the indexing pipeline (src/), parallel worker
pool, graph buffer with merge support, SQLite writer, and 1893-test suite.
Linter setup: zero warnings from clang-tidy (all checks enabled, no NOLINT
suppressions), cppcheck, and clang-format. All issues fixed at source —
proper headers for external linkage, GROW_ARRAY macro restructured to
eliminate type parameter, null-deref paths guarded, named intermediates
for suspicious-argument checks.
Martin Vogel