docs(cli,ledger): sweep #159 demo-retirement drift — stale comments + ledger notes

Cycle-close audit tidy for the #159 demo-retirement arc: behaviour-free
reword of prose/comments/docs left pointing at symbols the arc deleted.
Adversarially verified by the audit workflow; cargo build --workspace
--all-targets green.

- README: drop the removed `--harness` token; restrict the legacy built-in
  form claim to walkforward/mc/generalize (run/sweep no longer resolve one).
- glossary: the built-in `--strategy` sweep surface is retired (#159), not a
  live inline path.
- INDEX.md ledger: append [HISTORY] supersession markers (house style) to the
  dated realization notes advertising the retired `--harness` / built-in
  `--strategy` CLI forms (cost-flag #153, cycles 0065/0066/0067, name-res,
  #210 status); historical text preserved.
- aura-engine test-fixture docs: drop dead cross-crate refs to the deleted
  aura-cli fns sample_harness / build_sample and the deleted `macd` composite.
- cli_run.rs: reword the #159-cut-2 pin doc to the current clap generic-usage
  reality (no strategy_from / Strategy::RBreakout); r_sma_sweep_family ->
  blueprint_sweep_family.
- verb_sugar.rs: fix the pre-existing `E[R]` unresolved-doc-link warning.

Remaining tidy — the main.rs comment cluster plus its rustdoc link at :1546
(the second cargo-doc warning) — held for a follow-up issue. The dead
cost-graph branch is tracked in #221. refs #159

crates/aura-cli/src/verb_sugar.rs

@@ -512,7 +512,7 @@ pub(crate) struct GeneratedMc {
 /// Translate one `aura mc --strategy r-sma --real` invocation into its two generated
 /// documents: a `[std::sweep(argmax), std::walk_forward, std::monte_carlo]` process
 /// (the sweep enumerates the IS-refit survivor grid for the wf stage; the terminal
-/// monte_carlo stage pools the per-window OOS trade-R series and r-bootstraps E[R])
+/// monte_carlo stage pools the per-window OOS trade-R series and r-bootstraps `E[R]`)
 /// and a campaign running the fast/slow grid over one instrument under a single risk
 /// regime that carries the stop. Unlike `translate_walkforward` (which hardcodes
 /// `seed: 0`), `translate_mc` sets `campaign.seed = seed` (the mc `--seed`): the wf