feat(dynamics): add PlusDI, MinusDI, PlusDM, MinusDM indicators

Complete thin Dx-composition wrapper indicators with full test coverage:

- PlusDi/MinusDi: Directional Indicator wrappers (DiPlus/DiMinus from Dx)
- PlusDm/MinusDm: Directional Movement wrappers (DmPlus/DmMinus from Dx)
- Individual validation tests per indicator directory (TALib, Skender, bounds)
- Combined unit tests (DiDm.Tests.cs) and validation tests (DiDm.Validation.Tests.cs)
- Quantower wrappers + tests for all 4 indicators
- PineScript v6 implementations with compensated RMA
- Normalized .md documentation for all indicators and categories
- 182 tests passing, 0 failures

lib/filters/elliptic/Elliptic.md

@@ -1,5 +1,7 @@
 # ELLIPTIC: 2nd Order Elliptic Lowpass Filter
 
+> *If you want a vertical cliff, you have to accept a few bumps on the plateau.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Filter                        |
@@ -17,8 +19,6 @@
 - Requires `period` bars of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "If you want a vertical cliff, you have to accept a few bumps on the plateau."
-
 The Elliptic filter (or Cauer filter for the history buffs) is the uncompromising extremist of linear filtering. It offers the steepest possible roll-off for a given order, but extracts a heavy price: ripple in both the passband and the stopband. While Butterworth is polite and Chebyshev is opinionated, Elliptic is aggressive. This implementation delivers a sharp 2nd-order Lowpass response with **1dB passband ripple** and a crushing **40dB stopband attenuation**.
 
 ## Historical Context