feat(native-host): kill previous instance on startup and in installers

- Add kill-previous-instance.js with PID lock file under BASE_DIR
- On startup, send SIGTERM to any existing native-host process before binding ports
- Register removePidFile on shutdown and exit so the lock is cleared
- Run "stop any running native host" at the start of install.sh and install.ps1
- Add kill-previous-instance.js to CI syntax check

scripts/install.ps1

@@ -20,6 +20,10 @@ Write-Host "==========================" -ForegroundColor Cyan
 Write-Host "Install : $InstallDir"
 Write-Host ""
 
+# ── Stop any running native host first ─────────────────────────────────────────
+Write-Host "Stopping any running native host..."
+Get-Process | Where-Object { $_.Path -like "*holesail-browser-host*" } | Stop-Process -Force -ErrorAction SilentlyContinue
+
 # ── Preserve user data from any previous installation ─────────────────────────
 $StashDir     = Join-Path $env:TEMP "holesail-browser-stash-$([System.Guid]::NewGuid().ToString('N'))"
 $StashStorage = Join-Path $StashDir "holesail-browser-storage"
@@ -42,9 +46,8 @@ if (Test-Path $InstallDir) {
   $HadPrevious = $true
 }
 
-# ── Stop any running instance ──────────────────────────────────────────────────
+# ── Remove previous installation ──────────────────────────────────────────────
 Write-Host "Removing any previous installation..."
-Get-Process | Where-Object { $_.Path -like "*holesail-browser-host*" } | Stop-Process -Force -ErrorAction SilentlyContinue
 if (Test-Path $InstallDir) { Remove-Item $InstallDir -Recurse -Force }
 
 # Remove old registry entries

scripts/install.sh

@@ -34,6 +34,11 @@ echo "Platform : ${PLATFORM}-${ARCH}"
 echo "Install  : ${INSTALL_DIR}"
 echo ""
 
+# ── Stop any running native host first ────────────────────────────────────────
+echo "Stopping any running native host..."
+pkill -f "holesail-browser/native-host/index.mjs" 2>/dev/null || true
+pkill -f "holesail-browser-host" 2>/dev/null || true
+
 # ── Preserve user data from any previous installation ─────────────────────────
 STASH_DIR="$(mktemp -d)"
 STASH_STORAGE="${STASH_DIR}/holesail-browser-storage"
@@ -51,10 +56,8 @@ if [[ -d "$INSTALL_DIR" ]]; then
   HAD_PREVIOUS=true
 fi
 
-# ── Stop any running instance ──────────────────────────────────────────────────
+# ── Remove previous installation ──────────────────────────────────────────────
 echo "Removing any previous installation..."
-pkill -f "holesail-browser/native-host/index.mjs" 2>/dev/null || true
-pkill -f "holesail-browser-host" 2>/dev/null || true
 rm -rf "$INSTALL_DIR"
 
 # Remove old native messaging manifests