Implement Substation: BLE-WS bridge with music-reactive e-stim

- Renamed from CoyoteBridge to Substation (namespace, classes, UI)
- BLE connection via WinRT with graceful disconnect handling
- WebSocket server (127.0.0.1:8765) with single-client, push events
  for BLE connect/disconnect transitions
- Operator strength limiter (clamp/scale modes, default 30)
- Tray icon with 3 states: neutral/active/hot (runtime-drawn voltage glyph)
- A/B strength gauges, hide-on-minimise to tray
- Music mode: MP3 decode + FFT analysis (NAudio + FftSharp), rhythm→ch A,
  melody→ch B, pre-analyzed with synced audio playback
- Test/Stop All work without BLE connected (dev mode)
- WS device-driving commands error when BLE not connected; ping/status/
  connect always work
- TreatWarningsAsErrors, LangVersion=latest
- .gitignore, README with full API docs + attribution

Substation.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net8.0-windows10.0.19041.0</TargetFramework>
+    <SupportedOSPlatformVersion>10.0.17763.0</SupportedOSPlatformVersion>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <UseWindowsForms>true</UseWindowsForms>
+    <LangVersion>latest</LangVersion>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <AssemblyName>Substation</AssemblyName>
+    <RootNamespace>Substation</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="NAudio" Version="2.2.1" />
+    <PackageReference Include="FftSharp" Version="2.1.0" />
+  </ItemGroup>
+
+</Project>