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Subplan 02 Slice 2 foundation. vendor/sqlite/ holds the amalgamation (provenance + upgrade notes in its README); make build compiles it into build/vendor/libsqlite3.a (statically linked into dist via -L) and build/vendor/jit/libsqlite3.dylib (dlopen'd by sx run via tests/run.sh's -L flag) — separate directories because the macOS linker prefers a dylib over an archive in one search dir. The sx JIT resolves #foreign symbols via dlsym(RTLD_DEFAULT), where the already-loaded OS libsqlite3 wins by load order — so the vendored build renames its API to dist_sqlite3_* (vendor/sqlite/rename.h, -include'd), making resolution unambiguous in both modes: those symbols exist only in the vendored products. src/db/sqlite.sx binds the renamed surface behind Sqlite/SqliteStmt (open/exec/prepare/bind/step/column/finalize, errmsg, last_insert_rowid, changes, libversion); opaque handles cross the FFI as usize, strings read from sqlite are copied before its buffers die. make test 20/20 (new: sqlite_smoke.sx — pins the loaded version to the vendored 3.53.2, round trip, reopen persistence, BEGIN/ROLLBACK, errmsg; also verified as an AOT binary with no libsqlite3 in otool -L).