- Move binary to /usr/lib/fortress/fortress (out of PATH)
- Add wrapper script /usr/bin/fortress that calls the binary
- Eliminate fortress-bin naming convention
- Add flake.nix for NixOS users
- Update shell integrations (fortress.sh, fortress.fish) with better path detection
- Add CLAUDE.md for Claude Code guidance
- Support /usr/lib64 path for 64-bit RPM systems