#269 Accept move destination directories

[bsutton]

Summary

• treat variable and form move destinations as directories rather than stored entry names
• accept conventional trailing slashes and the logical root destination
• continue validating each calculated target through the core path/name types
• cover the reported /X/A/A to /X/ CLI flow

Validation

• cargo fmt --all -- --check
• cargo clippy --locked -p revault_cli --all-targets -- -D warnings
• cargo test --locked -p revault_cli move_tests
• cargo test --locked -p revault_cli --test cli_flow file_env_and_developer_aliases_execute_real_flows -- --exact --nocapture

Closes #269