Expand description
Repository discovery and identity via gix (spec §4 read operations):
discovery from a directory upward, bare detection, and the current worktree.
Resolving the primary worktree root is done from git rev-parse --git-common-dir (in open_session) rather than from gix, because gix’s
common_dir() does not resolve the linked-worktree indirection reliably — a
fallback the spec §4 explicitly sanctions.