Lay Pure out as a core with the parts selected around it

The app model, the tree store and the HTTP host lived in
prototypes/connections among the earlier document runtime, the store was
known only by its format's name, and Vega compiled six Pure sources by path.
Now, as the README's principle has it:

  core/   runtime, flow and the app model (module*.c), with what the core
          asks of storage (state.h, store.h)
  store/  the tree store (PURETRE3, PUREREC1)
  serve/  pure-serve: HTTP host, outbound delivery, JSON in place
  cli/    pure-run, pure-edit-module

A top-level make builds libpure.a (app model and store, for hosts to link)
and the hosts; make check runs the store's and the app model's tests. The
earlier runtime still builds from prototypes/connections against core/ and
store/ (check, check-tree and check-core pass). Design 009 records the rule:
parts by role behind libraries; git repositories split by coupling, so the
store stays here while its contract moves with the core, and Vega stays apart.

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/research/019-byte-storage.md b/docs/research/019-byte-storage.md
index faefecf..b58adcd 100644
--- a/docs/research/019-byte-storage.md
+++ b/docs/research/019-byte-storage.md
@@ -72,7 +72,7 @@ Linux AArch64에서 일반 빌드와 ASan·UBSan 빌드가 모두 통과했다.
 
 [원자료와 재현](../../prototypes/connections/results/2026-09-23-byte-storage/README.md),
 [직접 저장 구현](../../prototypes/connections/store.c),
-[구간·수명 API](../../prototypes/connections/store.h).
+[구간·수명 API](../../core/store.h).
 018의 원자료는 당시 SQLite 구현의 기록으로 별도 보존한다.
 
 ## 다음 결정