fix: require feedback on post rejection, post-specific review text, show superadmins in team list

- Reject requires feedback on both client and server (400 if empty)
- PublicPostReview uses post-specific i18n keys instead of artefact ones
- Team list always includes superadmins/managers for non-superadmin users

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

client/src/i18n/en.json

@@ -902,5 +902,11 @@
   "posts.submitForReview": "Submit for Review",
   "posts.schedulePost": "Schedule Post",
   "review.postReview": "Post Review",
-  "review.createdBy": "Created by"
+  "review.createdBy": "Created by",
+  "review.confirmApprovePost": "Approve this post?",
+  "review.confirmRejectPost": "Reject this post?",
+  "review.confirmApprovePostDesc": "Are you sure you want to approve this post?",
+  "review.confirmRejectPostDesc": "Are you sure you want to reject this post? Please provide feedback explaining why.",
+  "review.feedbackRequired": "Feedback (required)",
+  "review.feedbackRequiredError": "Please provide feedback when rejecting"
 }