3dac2c0c99
Since cycle 0045 the flat runs.jsonl store has had no producer (sweep/mc/ walkforward persist to the family store; `aura run` does not persist), so `aura runs list` / `runs rank` read a store nothing populates — a live dead-end surface, the honesty gap the Runway milestone closes. Resolve the C18 deferred fork (INDEX.md) as (b) RETIRE: drop the two CLI commands + their dispatch arms, usage fragments, and the now-unused load_runs_or_exit. Families (sweep/mc/walkforward, C21) subsume standalone over-time comparison. The aura-registry flat lib API (append/load/rank_by/optimize) is RETAINED — optimize backs walk-forward's in-sample step, rank_by backs `runs family ... rank`. `runs families` / `runs family` are untouched. Decision recorded on #73 (user-directed (b), 2026-06-18). Cosmetic sub-item (json! family-wrapper -> to_json() stdout key-order unification) deferred to a follow-up: json! routes the embedded report through serde_json::Value, which re-alphabetizes keys, so it needs manual JSON construction, not a trivial swap. RED-first: the retire test asserted `runs list`/`rank` now exit 2 (was exit 0). Verified: cargo build --workspace, clippy --all-targets -D warnings, and cargo test --workspace all green. closes #73