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/oscillators/gator/Gator.md

@@ -1,5 +1,7 @@
 # GATOR: Williams Gator Oscillator
 
+> *The alligator tells you the trend exists. The gator tells you whether the alligator is hungry or full.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Oscillator                        |
@@ -16,8 +18,6 @@
 - Requires `Math.Max(jawPeriod + jawShift, Math.Max(teethPeriod + teethShift, lipsPeriod + lipsShift))` bars of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "The alligator tells you the trend exists. The gator tells you whether the alligator is hungry or full."
-
 The Williams Gator Oscillator is a dual-histogram visualization of the Alligator indicator's convergence and divergence. It strips the Alligator's three SMMA lines down to two absolute differences: upper (Jaw minus Teeth) and lower (negative of Teeth minus Lips). The result is a zero-centered oscillator where expanding bars signal trend acceleration and contracting bars signal trend exhaustion. Because it operates on pre-computed SMMA values, the Gator adds zero computational overhead beyond two subtractions, two absolute values, and one sign flip per bar.
 
 ## Historical Context