Decode the original project path from the .claude/projects folder name.
First tries walking the filesystem to find the exact directory (handles ambiguous
encodings like spaces, parentheses, dots all becoming -).
Falls back to naive string-based decoding.
Walk the filesystem to find the original directory whose Claude-encoded form
matches remaining_encoded (the full encoded directory name without leading -).
full_target is the original complete encoded name for round-trip validation.