Client: build AppImages for older glibc

Co-Authored-By: Claude Opus 5.5 <[email protected]>

Client/Packaging/RestoreLibraryPath.py

@@ -0,0 +1,11 @@
+# PyInstaller runtime hook. The frozen app runs with LD_LIBRARY_PATH pointing
+# at its bundled libraries, and programs it starts inherit that: Flet's
+# desktop client then loads the bundled (older) libstdc++ instead of the
+# system's and won't start ("GLIBCXX_3.4.29 not found"). Give them the
+# original value back; the app itself has already loaded what it needs.
+import os
+
+if "LD_LIBRARY_PATH_ORIG" in os.environ:
+    os.environ["LD_LIBRARY_PATH"] = os.environ["LD_LIBRARY_PATH_ORIG"]
+else:
+    os.environ.pop("LD_LIBRARY_PATH", None)