fix(sqlite-objstore): make hex-id buffer size a compile-time constant for MSVC

[gabewillen]

Round 3 of the Windows port for the npm release of @augmem/cortext v1.3.3
(follow-up to PR #22 dirent and PR #23 unistd/fcntl). After those, both
Windows matrix jobs failed with:

backend_file.c(603,35): error C2057: expected constant expression
backend_file.c(603,15): error C2466: cannot allocate an array of constant size 0
backend_file.c(603,8): error C2133: 'hex_id': unknown size

MSVC C does not treat a static const size_t as a compile-time constant, so
char hex_id[kObjstoreIdHexChars + 1] is a VLA. This turns kObjstoreIdHexChars
into a #define of OBJSTORE_ID_SIZE * 2 (already a preprocessor constant).
No other const-sized stack arrays exist in the embedded objstore sources.

[Copilot]

Pull request overview

This PR fixes an MSVC C build failure in the embedded sqlite-objstore file backend by making the hex-ID buffer length a compile-time constant (avoiding MSVC treating a static const size_t as a non-constant and therefore producing a VLA error).

Changes:

• Replace static const size_t kObjstoreIdHexChars with a preprocessor constant so char hex_id[kObjstoreIdHexChars + 1] is a true constant-sized stack array under MSVC C.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.