Centralize slash command parsing in the commands crate so the REPL can share help metadata and grow toward Claude Code parity without duplicating handlers. This adds shared /help and /model parsing, routes REPL dispatch through the shared parser, and upgrades /status to report model and token totals.
To satisfy the required verification gate, this also fixes existing workspace clippy and test blockers in runtime, tools, api, and compat-harness that were unrelated to the new command behavior but prevented fmt/clippy/test from passing cleanly.
Constraint: Preserve existing prompt-mode and REPL behavior while adding real slash commands
Constraint: cargo fmt, clippy, and workspace tests must pass before shipping command-surface work
Rejected: Keep command handling only in main.rs | would deepen duplication with commands crate and resume path
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Extend new slash commands through the shared commands crate first so REPL and resume entrypoints stay consistent
Tested: cargo fmt; cargo clippy --workspace --all-targets -- -D warnings; cargo test --workspace
Not-tested: live Anthropic network execution beyond existing mocked/integration coverage
