fix: address review comments

- Use single quotes for description in ospo-contributors-report.md
- Define 60_DAYS_AGO and 30_DAYS_AGO variables in org-health Step 1

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: ashleywolf

workflows/ospo-contributors-report.md

@@ -1,6 +1,6 @@
 ---
 name: 'OSPO Contributors Report'
-description: "Monthly contributor activity metrics across an organization's repositories."
+description: 'Monthly contributor activity metrics across an organization''s repositories.'
 metadata:
   triggers: ['schedule', 'workflow_dispatch']
 labels: ['ospo', 'reporting', 'contributors']

workflows/ospo-org-health.md

@@ -63,6 +63,8 @@ PERIOD_DAYS = 30
 SINCE = date 30 days ago (ISO 8601)
 STALE_ISSUE_DAYS = 60
 STALE_PR_DAYS = 30
+60_DAYS_AGO = date 60 days ago (ISO 8601)
+30_DAYS_AGO = date 30 days ago (ISO 8601, same as SINCE)
 ```
 
 ## Step 2 — Gather Organization-Wide Aggregates (Search API)