preserve flash / full erase flash

- preserve: bonding 정보 및 settings/NVS 유지, application만 다시 올리는 용도

tools/flash_full_erase.ps1

@@ -0,0 +1,19 @@
+param(
+    [string]$Hex = "build\merged.hex"
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$RepoRoot = Split-Path -Parent $PSScriptRoot
+$HexPath = Join-Path $RepoRoot $Hex
+
+if (-not (Test-Path -LiteralPath $HexPath)) {
+    throw "Hex file not found: $HexPath. Build the project first."
+}
+
+Write-Host "[FLASH] FULL ERASE mode"
+Write-Host "[FLASH] This wipes application flash, NVS/settings, and BLE bonds."
+Write-Host "[FLASH] Programming: $HexPath"
+
+nrfjprog --program $HexPath --chiperase --verify --reset

tools/flash_preserve_settings.ps1

@@ -0,0 +1,29 @@
+param(
+    [string]$Hex = "build\merged.hex",
+    [string]$BuildDir = "build"
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = "Stop"
+
+$RepoRoot = Split-Path -Parent $PSScriptRoot
+$HexPath = Join-Path $RepoRoot $Hex
+$BuildPath = Join-Path $RepoRoot $BuildDir
+$Cmake = "C:\ncs\toolchains\fd21892d0f\opt\bin\cmake.exe"
+if (-not (Test-Path -LiteralPath $Cmake)) {
+    $Cmake = "cmake"
+}
+
+Write-Host "[FLASH] Rebuilding: $BuildPath"
+& $Cmake --build $BuildPath
+
+if (-not (Test-Path -LiteralPath $HexPath)) {
+    throw "Hex file not found: $HexPath. Build the project first."
+}
+
+Write-Host "[FLASH] PRESERVE mode"
+Write-Host "[FLASH] Uses sector erase, so NVS/settings and BLE bonds are preserved if the hex has no records in settings_storage."
+Write-Host "[FLASH] settings_storage is expected at 0xFE000-0x100000 for this project."
+Write-Host "[FLASH] Programming: $HexPath"
+
+nrfjprog --program $HexPath --sectorerase --verify --reset