HolographicMemoryProvider.shutdown() dropped its MemoryStore reference
without calling the existing MemoryStore.close(). Since the connection is
opened check_same_thread=False (one per session), its fd was released by
refcount/GC at a non-deterministic time on a non-deterministic thread,
churning a DB fd through the kernel free pool on every session teardown.
Call close() so the fd is released deterministically.
Reported by @alfranli123 (#44037), who pinpointed the exact code location.
Note: the report's TLS-fd-recycle corruption attribution could not be
reproduced from the code — dropping a sqlite connection flushes valid
SQLite pages via the VFS, never TLS framing, and the provider is at most a
releaser of DB fds, not a TLS-flushing socket owner. This change is correct
resource hygiene that removes per-session fd churn regardless.
7c0a5def58