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/voss/Voss.md

@@ -1,5 +1,7 @@
 # VOSS: Ehlers Voss Predictive Filter
 
+> *The best filter is one that tells you what is about to happen, not what already did.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Filter                        |
@@ -16,8 +18,6 @@
 - Requires `period` bars of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "The best filter is one that tells you what is about to happen, not what already did." — paraphrasing Ehlers
-
 ## Introduction
 
 The Voss Predictive Filter is a two-stage signal processing pipeline that extracts a dominant cycle from noisy price data and then predicts its future trajectory using negative group delay. Stage 1 is a two-pole bandpass filter (BPF) that isolates cycles near a specified period. Stage 2 is the Voss predictor, which applies a weighted feedback summation over past output values to shift the filter response forward in time. The result is a leading oscillator that anticipates bandpass zero crossings by a configurable number of bars. Crossings between the Filt (bandpass) and Voss (predictor) lines generate early trade signals with reduced lag.