fix: stage C++ integrator headers (EPMDev, UDASDev) into installer payload

build-installer.ps1's interfaces\ staging step only copied Python and C#
bindings into the installer payload, never the loose C++ headers under
interfaces\C++\EPMDev\ and interfaces\C++\UDASDev\. These headers have no
compiled library of their own -- C++ integrators build directly against
them -- so omitting them from the installer silently drops a supported
integration path with no error, even though a real PROD installation
ships these headers under Qualcomm\Alpaca\ (formerly ships them via the
downstream Alpaca-branded packaging that consumes this installer).

Fix: stage interfaces\C++\EPMDev\*.h and interfaces\C++\UDASDev\*.h into
the installer payload's interfaces\C++\{EPMDev,UDASDev}\ alongside the
existing Python/C# staging, following the same Test-Path-guarded pattern
already used for those languages.

Verified: rebuilt the Windows installer with this change from a real
release checkout and confirmed both header sets are present in the
resulting payload.zip under interfaces\C++\.

Signed-off-by: Hang Zhao (QCT) <hangz@qti.qualcomm.com>

Author: hangzqcom

packaging/windows/build-installer.ps1

@@ -112,6 +112,19 @@ if (Test-Path (Join-Path $SourceRoot 'examples')) {
 
 $interfacesDest = Join-Path $data 'interfaces'
 New-Item -ItemType Directory -Force -Path $interfacesDest | Out-Null
+# C++ integrator headers (no compiled library -- consumers build against these
+# directly). Matches PROD parity: PROD ships interfaces\C++\{EPMDev,UDASDev}\ headers.
+foreach ($cppMod in @('EPMDev', 'UDASDev')) {
+    $cppHeaderSrc = Join-Path $SourceRoot "interfaces\C++\$cppMod"
+    if (Test-Path $cppHeaderSrc) {
+        $cppHeaderDest = Join-Path $interfacesDest "C++\$cppMod"
+        New-Item -ItemType Directory -Force -Path $cppHeaderDest | Out-Null
+        Copy-Item (Join-Path $cppHeaderSrc '*.h') $cppHeaderDest -Force
+    } else {
+        Write-Warning "No interfaces\C++\$cppMod directory found; C++ headers will be absent from the installer."
+    }
+}
+
 foreach ($lang in @('Python', 'C#')) {
     $srcLang = Join-Path $SourceRoot "interfaces\$lang"
     if (Test-Path $srcLang) {
@@ -166,4 +179,4 @@ if (-not (Test-Path $setup)) { throw "IExpress did not produce $setup." }
 
 Write-Host ""
 Write-Host "Installer created: $setup"
-Write-Host ("  size: {0:N1} MB" -f ((Get-Item $setup).Length / 1MB))
+Write-Host ("  size: {0:N1} MB" -f ((Get-Item $setup).Length / 1MB))