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/errors/logcosh/LogCosh.md

@@ -1,5 +1,7 @@
 # Log-Cosh: Logarithm of Hyperbolic Cosine Loss
 
+> *The smooth operator that acts like L2 for small errors and L1 for large ones.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Error Metric                        |
@@ -16,8 +18,6 @@
 - Requires 1 bar of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "The smooth operator that acts like L2 for small errors and L1 for large ones."
-
 Log-Cosh Loss combines the best properties of L1 (absolute) and L2 (squared) error metrics through the logarithm of the hyperbolic cosine function. It provides smooth gradients everywhere while remaining robust to outliers.
 
 ## Historical Context