Fold LEGACY into the generation folders

The LEGACY copies of HexapodRobot, Hexapod_NEW, Hexapod_Teensy and the old remote sketch were identical to the imported repos and are removed. The old Nextion design moves to 2019-teensy-nrf24/remote-nextion/, the 2019 remote case files to 2019-teensy-nrf24/remote-case/. Paths in CLAUDE.md, READMEs, remote/ comments, sim/build.ps1, the Unity DLL message and .vscode/settings.json now point to the new places. robot/ is not touched (its CLAUDE.md asks to check with the owner first).

2026-current/sim/README.md

@@ -32,7 +32,7 @@ mistakes.
 
 Needs a 64-bit g++ and CMake. Strawberry Perl's `C:\Strawberry\c\bin` has
 g++, cmake and ninja, and the script falls back to it automatically. From
-the repo root in PowerShell:
+the `2026-current` folder in PowerShell:
 
 ```
 .\sim\build.ps1             # configure (first time) + build + smoke test

2026-current/sim/build.ps1

@@ -1,5 +1,5 @@
 # Builds the firmware simulation DLL and runs the headless smoke test.
-# Windows PowerShell 5.1 compatible. From the repo root:
+# Windows PowerShell 5.1 compatible. From the 2026-current folder:
 #
 #   .\sim\build.ps1             configure (first time) + build + smoke test
 #   .\sim\build.ps1 -NoTest     build only