fix: add app/src to embedded Python ._pth for module discovery

Windows embedded Python ignores PYTHONPATH when a ._pth file exists.
Add ../app/src to the ._pth so wled_controller is importable.
Fixes ModuleNotFoundError on portable builds.

build-dist-windows.sh

@@ -73,11 +73,16 @@ if [ -z "$PTH_FILE" ]; then
     exit 1
 fi
 
-# Uncomment 'import site' and add Lib\site-packages
+# Uncomment 'import site', add Lib\site-packages and app source path
 sed -i 's/^#\s*import site/import site/' "$PTH_FILE"
 if ! grep -q 'Lib\\site-packages' "$PTH_FILE"; then
     echo 'Lib\site-packages' >> "$PTH_FILE"
 fi
+# Embedded Python ._pth overrides PYTHONPATH, so we must add the app
+# source directory here for wled_controller to be importable
+if ! grep -q '\.\./app/src' "$PTH_FILE"; then
+    echo '../app/src' >> "$PTH_FILE"
+fi
 echo "  Patched $(basename "$PTH_FILE")"
 
 # ── Download pip and install into embedded Python ────────────