The name-based sibling probe can't reach every dead worktree: a dir renamed away
from its repo's prefix (`hermes-salvage-drafts` next to `hermes-agent`) shares
nothing to trim back to, and a scratch dir under /tmp was never a worktree at
all. Those fall through to the path-only heuristic, which reports the cwd as its
own repo root, and Tier 2 promotes it to a top-level project — one that can't be
opened and can only be dismissed by hand.
Gate auto-project promotion on the directory still existing, threaded in as an
injected predicate to keep the builder pure. The guard keys on the directory,
not on git-ness, so a plain non-git folder that's still on disk keeps its
project; callers that can't stat (remote backends) omit it and keep every
candidate. A stale persisted `git_repo_root` gets the same treatment, so a
deleted repo can't resurrect from the recorded value alone.
Brooklyn Nicholson
b572ec3dda