sol: fix CHECK gate path resolution

wizard-work/sol/CHECK-working-tree-triage-2026-11-02

@@ -1,9 +1,14 @@
 #!/usr/bin/env bash
 # CHECK -- sol: working-tree triage (modified tracked files vs HEAD).
-# Exit 0 iff the committed manifest re-derives from each recorded path and every
-# frozen path still exists as a real file under the repo.
+# Exit 0 iff the committed manifest re-derives from each recorded path and
+# every frozen path still exists as a real file under the repo.
 set -u
-SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
-REPO_ROOT="$(cd "$SCRIPT_DIR" && pwd)"
-cd "$REPO_ROOT" || exit 2
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+# Resolve the repo root (this script may live inside wizard-work/sol/ or at the
+# repo root, so walk up to the directory that holds .git).
+ROOT="$(git -C "$HERE" rev-parse --show-toplevel 2>/dev/null)" \
+    || { echo "CANNOT GRADE: no git toplevel above $HERE" >&2; exit 2; }
+cd "$ROOT" || { echo "CANNOT GRADE: cannot cd to $ROOT" >&2; exit 2; }
+
 exec python3 wizard-work/sol/verify_working_tree_triage_2026_11_02.py