Clean up RFP ESP32-S3 target and tooling

tools/flash_rfp_s3.ps1

@@ -0,0 +1,44 @@
+param(
+  [string]$ComPort,
+
+  [switch]$BuildOnly
+)
+
+$ErrorActionPreference = "Stop"
+
+$scriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
+$repoRoot = Split-Path -Parent $scriptDir
+$envName = "rfp_esp32s3_wroom1_n16r8_3x106"
+$venvPython = Join-Path $repoRoot ".venv\Scripts\python.exe"
+
+if (-not $BuildOnly -and [string]::IsNullOrWhiteSpace($ComPort)) {
+  throw "ComPort is required unless -BuildOnly is used."
+}
+
+if (Test-Path $venvPython) {
+  $pythonCommand = $venvPython
+  $pythonArgs = @()
+} elseif (Get-Command py -ErrorAction SilentlyContinue) {
+  $pythonCommand = "py"
+  $pythonArgs = @("-3")
+} elseif (Get-Command python -ErrorAction SilentlyContinue) {
+  $pythonCommand = "python"
+  $pythonArgs = @()
+} else {
+  throw "No Python runtime found. Install Python or create .venv first."
+}
+
+$pioHome = Join-Path $repoRoot ".piohome"
+$env:PLATFORMIO_CORE_DIR = $pioHome
+$env:PLATFORMIO_PACKAGES_DIR = Join-Path $pioHome "packages"
+$env:PLATFORMIO_PLATFORMS_DIR = Join-Path $pioHome "platforms"
+$env:PLATFORMIO_CACHE_DIR = Join-Path $pioHome ".cache"
+$env:PLATFORMIO_BUILD_CACHE_DIR = Join-Path $pioHome "buildcache"
+
+$args = @("-m", "platformio", "run", "-e", $envName)
+if (-not $BuildOnly) {
+  $args += @("-t", "upload", "--upload-port", $ComPort)
+}
+
+& $pythonCommand @pythonArgs @args
+exit $LASTEXITCODE