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/momentum/vel/Vel.md

@@ -1,5 +1,7 @@
 # VEL: Jurik Velocity
 
+> *Momentum is easy. Smooth momentum without lag is hard. Jurik Velocity is the answer.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Momentum                        |
@@ -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.
 
-> "Momentum is easy. Smooth momentum without lag is hard. Jurik Velocity is the answer."
-
 Jurik Velocity (VEL) measures price rate-of-change through the differential between two weighted moving averages with distinct inertia profiles. Standard momentum ($P_t - P_{t-n}$) amplifies noise: single outlier bars create false signals. VEL exploits the different convergence speeds of Parabolic Weighted Moving Average (PWMA) and linear Weighted Moving Average (WMA) to isolate clean velocity information. The quadratic weighting of PWMA responds faster than linear WMA; their difference captures acceleration without bar-to-bar noise.
 
 ## Historical Context