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/volume/pvi/Pvi.md

@@ -1,5 +1,7 @@
 # PVI: Positive Volume Index
 
+> *High volume days reveal where retail traders swarm; smart money prefers the quiet.*
+
 | Property         | Value                            |
 | ---------------- | -------------------------------- |
 | **Category**     | Volume                        |
@@ -16,8 +18,6 @@
 - Requires `> 2` bars of warmup before first valid output (IsHot = true).
 - Validated against TA-Lib, Skender, and Tulip reference implementations where available.
 
-> "High volume days reveal where retail traders swarm; smart money prefers the quiet." — Norman Fosback
-
 The Positive Volume Index tracks price changes exclusively on days when trading volume increases compared to the previous day. The underlying theory: retail investors—the "uninformed crowd"—drive high-volume trading days, often reacting emotionally to news and price movements. Institutional investors prefer to operate during quieter periods to avoid moving markets.
 
 PVI essentially asks: "What are prices doing when the crowd is most active?" If PVI rises on high volume, retail enthusiasm is driving prices up. If PVI falls on high volume, retail panic may be pushing prices down. Either way, this represents the emotional, less-informed segment of the market.