fix: include git2/sys/alloc.h for git_allocator on libgit2 1.8+

[eejd]

Problem

git_allocator was moved from the top-level git2.h into git2/sys/alloc.h
in libgit2 1.8.0. Building codebase-memory-mcp against libgit2 ≥ 1.8 fails:

internal/cbm/cbm.c:347:12: error: unknown type name 'git_allocator'

Fix

Add an explicit #include <git2/sys/alloc.h> immediately after
#include <git2.h> inside the HAVE_LIBGIT2 guard in
internal/cbm/cbm.c. The struct members (gmalloc, grealloc, gfree)
and the GIT_OPT_SET_ALLOCATOR option code are unchanged — the only
issue was the missing header.

Tested against

• libgit2 1.9.4 (MacPorts, macOS / Apple Silicon)

🤖 Generated with Claude Code

[DeusData]

Thanks @eejd — the git2/sys/alloc.h include for libgit2 1.8+ is correct. The only thing blocking is DCO: the commit's author email doesn't match its Signed-off-by email, so the DCO check fails. Could you re-sign with a matching identity — git commit --amend -s (with the author email equal to your sign-off email), or git rebase --signoff — then force-push? Once DCO is green I'll merge. 🙏