Add heuristic (4) to findProjectRoot: after heuristics (1)-(3) (sub_repos,
multiRepo, .git+parent-.planning/) are exhausted without a match, perform a
second bounded walk-up within FIND_PROJECT_ROOT_MAX_DEPTH to locate the
nearest ancestor directory containing a .planning/ subdirectory. Returns that
ancestor as the project root, so loadConfig finds the correct config instead
of falling through to defaults when gsd-tools is invoked from a plain
descendant subdirectory of a single-repo project (#1366 cwd-drift gap).
Ordering is load-bearing: the new walk runs AFTER the existing loop so
sub_repos workspaces (where a child sub-repo may have its own .planning/)
still resolve correctly to the parent workspace. The existing own-.planning/
guard (heuristic 0, #1362) and the depth bound (FIND_PROJECT_ROOT_MAX_DEPTH=10)
are both preserved unchanged.
Part of #1411
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
