fix: use try/except import for ComfyUI and pytest compatibility

ComfyUI loads custom nodes as packages (relative import needed),
pytest runs at top level (absolute import needed). Handle both.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

__init__.py

@@ -1,4 +1,7 @@
-from immich_nodes.save_to_immich import SaveToImmich
+try:
+    from .immich_nodes.save_to_immich import SaveToImmich
+except ImportError:
+    from immich_nodes.save_to_immich import SaveToImmich
 
 NODE_CLASS_MAPPINGS = {
     "SaveToImmich": SaveToImmich,