This adds a lightweight session home for the Rust CLI, auto-persists REPL state, and exposes list, search, show, and named resume flows so users no longer need to remember raw JSON paths.
The change keeps the old --resume SESSION.json path working while adding friendlier session discovery. It also makes API env-based tests hermetic so workspace verification remains stable regardless of shell environment.
Constraint: Keep session UX incremental and CLI-native without introducing a new database or TUI layer
Constraint: Preserve backward compatibility for the existing --resume SESSION.json workflow
Rejected: Build a richer interactive picker now | higher implementation cost than needed for this parity slice
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep human-friendly session lookup additive; do not remove explicit path-based resume support
Tested: cargo fmt; cargo clippy --all-targets --all-features -- -D warnings; cargo test -q
Not-tested: Manual multi-session interactive REPL behavior across multiple terminals