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/statistics/cma/Cma.md

@@ -1,5 +1,7 @@
 # CMA: Cumulative Moving Average
 
+> *The running average that never forgets. Every single tick you've ever fed it? Still in there, affecting the result. It's like the elephant of technical indicators.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Statistic                        |
@@ -16,8 +18,6 @@
 - Requires `1` bars of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "The running average that never forgets. Every single tick you've ever fed it? Still in there, affecting the result. It's like the elephant of technical indicators."
-
 The Cumulative Moving Average (CMA) calculates the arithmetic mean of ALL data points seen so far, not just a fixed window. Unlike SMA or EMA which use a sliding window, CMA treats every historical value with equal weight. As the sample size grows, each new value has diminishing impact on the average.
 
 ## Historical Context