chore(desktop): rebase onto main — add react-day-picker, retain diff dep

Mechanical conflict resolution: origin/main added react-day-picker (status
indicators, #7112) while this branch replaced date-fns with diff (canvas
diff view). Merged result keeps both react-day-picker and diff, removes
date-fns from the desktop importer.

Co-authored-by: Will Pfleger <pfleger.will@gmail.com>
Signed-off-by: Will Pfleger <pfleger.will@gmail.com>

Author: Duncan

desktop/package.json

@@ -74,6 +74,7 @@
     "qrcode": "^1.5.4",
     "qrcode.react": "^4.2.0",
     "react": "^19.1.0",
+    "react-day-picker": "^10.0.1",
     "react-diff-view": "^3.3.2",
     "react-dom": "^19.1.0",
     "react-markdown": "^10.1.0",