Add automated weekly report for new files

[pwseg]

Proposed changes

• Added a GitHub Action that tracks new files added to the repo since mid-September.
• The platform team working on the migration needs a running list of new files since their initial snapshot.
• The action runs every Friday at noon ET and creates a GitHub issue with a list of all new files since September 17th.
• Each issue includes the file path/date added/commit link.
• I also created a migration label to add to this issue.
• We can also trigger the action manually from the Actions tab if we need an ad-hoc report.

Merge timing

• ASAP once approved

[forstisabella]

baller