docs: remove C# Implementation Considerations sections, clean up temp scripts, reorganize test files

- Remove 'C# Implementation Considerations' sections from 34 indicator .md files
- Delete 29 temp PowerShell scripts (_fix_mojibake.ps1, _hex_scan.ps1, etc.)
- Move test files into tests/ subdirectories for consistent project structure
- Add trader-focused bullet points to indicator documentation

lib/dynamics/vhf/tests/Vhf.Tests.cs

@@ -149,7 +149,7 @@ public class VhfTests
     public void Calc_IsNew_False_UpdatesValue()
     {
         var vhf = new Vhf(5);
-        var gbm = new GBM(startPrice: 100.0);
+        var gbm = new GBM(startPrice: 100.0, mu: 0.05, sigma: 0.2, seed: 42);
         var bars = gbm.Fetch(20, DateTime.UtcNow.Ticks, TimeSpan.FromMinutes(1));
 
         // Feed 10 bars to get past warmup