feat v1.23.2: raise the manual-upload limit to 50 MB

MAX_FILE_BYTES 25→50 MB (still enforced while the multipart body streams in);
frontend fallback in the error toast updated; TESTING.md row updated.

custom_components/houseplan/manifest.json

@@ -16,5 +16,5 @@
   "issue_tracker": "https://github.com/Matysh/houseplan-card/issues",
   "requirements": [],
   "single_config_entry": true,
-  "version": "1.23.1"
+  "version": "1.23.2"
 }