feat(family-09): add 7 trailing stops (HiLo, Volty, Yo-Yo, Donchian, Pct, Step, Renko) (#46)

* feat(family-09): add 7 trailing stops (HiLo, Volty, Yo-Yo, Donchian, Pct, Step, Renko)

Rounds out the Trailing Stops family from 5 to 12 indicators:

- HiLoActivator (Crabel): SMA-of-high/SMA-of-low trail with a one-bar
  lag; emits the opposite-side SMA as the trailing stop.
- VoltyStop (Cynthia Kase): ATR trail anchored on the extreme close
  since the trade was opened — tighter than AtrTrailingStop on
  pullbacks.
- YoyoExit: long-only ATR trail with an explicit re-entry trigger at
  trail + multiplier*ATR; exposes an in_trade flag.
- DonchianStop (Turtle): lowest low / highest high over the window;
  multi-output {stop_long, stop_short}.
- PercentageTrailingStop: fixed-percent trail that scales across
  instruments without per-asset tuning.
- StepTrailingStop: snaps to a step_size-aligned grid; mirrors
  discretionary stop-by-hand workflow.
- RenkoTrailingStop: block-anchored trail; only moves on full-block
  advances, ignores intra-block noise.

All seven are wired into wickra-core, the Python / Node / WASM
bindings, the indicator_update + indicator_update_candle fuzz targets,
the wickra bench harness, and the Python + Node test suites. README
counter bumps from 71 to 78; CHANGELOG entry under [Unreleased].

* fix(family-09): satisfy pedantic clippy lints

- hilo_activator: rewrite match-Some/None as if-let-else (single_match_else),
  add backticks around the HiLo identifier in module/struct doc (doc_markdown).
- percentage / step / renko trailing stop tests: use f64::from(i32) instead
  of `as f64` (cast_lossless).
- bench `benches()` is now >100 lines after Family 09 was wired in; allow
  too_many_lines (matches the python pymodule fn).

CHANGELOG.md

@@ -8,6 +8,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- **Family 09 — Trailing Stops, seven new indicators.** Rounds out the
+  trailing-stop family from 5 to 12: `HiLoActivator` (Crabel's
+  SMA-of-high / SMA-of-low trail), `VoltyStop` (Cynthia Kase's
+  extreme-anchor ATR stop), `YoyoExit` (long-only ATR trail with a
+  re-entry trigger), `DonchianStop` (the original Turtle exit, lowest
+  low / highest high), `PercentageTrailingStop` (fixed-percent trail),
+  `StepTrailingStop` (round-number grid trail) and `RenkoTrailingStop`
+  (block-anchored Renko-style trail). All wired into the four bindings
+  (Rust, Python, Node, WASM), the streaming + batch fuzz targets, and
+  the bench harness.
 - **Klinger Volume Oscillator (KVO).** Stephen J. Klinger's trend-aware
   volume-force oscillator: `EMA(vf, fast) − EMA(vf, slow)` over a daily
   volume force scaled by cumulative-measurement ratio. Classic