feat: add RRSI (Rocket RSI) — Ehlers TASC May 2018

Algorithm: SuperSmoother-filtered momentum → Ehlers RSI → Fisher Transform
- 2-pole Butterworth IIR pre-filter removes noise
- Ehlers RSI (raw summation, not Wilder) outputs [-1,1]
- arctanh produces Gaussian-distributed zero-mean oscillator

Files: Rrsi.cs, Rrsi.Quantower.cs, Rrsi.md, 31+7 tests
Integration: sidebar, indices, Python bridge (Exports, _bridge, oscillators, SPEC)
Build: 0 warnings, 0 errors | Tests: 15,963 passed, 0 failed

python/quantalib/oscillators.py

@@ -25,6 +25,7 @@ __all__ = [
     "qqe",
     "reverseema",
     "rvgi",
+    "rrsi",
     "smi",
     "squeeze",
     "stc",
@@ -283,6 +284,17 @@ def rvgi(open: object, high: object, low: object, close: object, period: int = 1
     return _wrap_multi({"rvgiOutput": rvgiOutput, "signalOutput": signalOutput}, idx, "oscillators", offset)
 
 
+def rrsi(close: object, smoothLength: int = 10, rsiLength: int = 10, offset: int = 0, **kwargs) -> object:
+    """Rocket RSI (Ehlers) — Fisher Transform of Super Smoother–filtered RSI."""
+    src = _to_np(close)
+    n = len(src)
+    out = _np.empty(n, dtype=_np.float64)
+    _bridge._check(_bridge._lib.qtl_rrsi(
+        src.ctypes.data_as(_bridge._dp), n,
+        out.ctypes.data_as(_bridge._dp), smoothLength, rsiLength))
+    return _shift(out, offset)
+
+
 def smi(high: object, low: object, close: object, kPeriod: int = 14, kSmooth: int = 3, dSmooth: int = 3, blau: int = 3, offset: int = 0, **kwargs) -> object:
     """Stochastic Momentum Index."""
     kPeriod = int(kPeriod)