QA: Team Coupon Redemption Notifications

[ebuwen88]

Source PRD: docs/prds/team-coupon-redemption-notifications.md (no GitHub PRD issue exists for this one)

Note: This feature is already implemented (couponRedemptionNotifications table,
notificationService.ts coupon-redemption functions, teamService.getTeamAdmins,
redeemCoupon routed through enrollUser + multi-admin notify, /team unread badge
and per-row "New" indicator) despite its plan doc
(docs/plans/team-coupon-redemption-notifications.md) still saying
"Status: Proposed." teamService.test.ts (16), couponService.test.ts (16), and
notificationService.test.ts (24) all pass. This issue is for a fresh,
independent manual QA sign-off against the PRD's requirements — not
implementation tracking.

Instructor Notification Parity (PRD Functional #1)

• Redeeming a coupon enrolls the student via the same path as a direct purchase (enrollUser)
• A team-coupon redemption produces an instructor notification, same as a direct-purchase enrollment
• A failed redemption (bad code, already consumed, already enrolled, country mismatch) produces no instructor notification

Team Admin Notification Creation (PRD Functional #2, #7)

• Redeeming a coupon creates a notification for that coupon's team admin
• On a team with multiple admins, redeeming a coupon notifies every admin, not just one
• A failed redemption produces no coupon-redemption notification

/team Unread Count (PRD Functional #3)

• /team shows an unread-notification count for the signed-in team admin
• Count reflects only unread redemption notifications

Per-Coupon "New" Indicator (PRD Functional #4)

• A redeemed coupon row shows a "New" badge distinct from the existing "Claimed by ..." text, when unread
• The "New" badge disappears after the admin has viewed /team once

Read State on Page Load (PRD Functional #5)

• Loading /team marks that admin's redemption notifications as read
• Notifications still render as "New" in the same response that marks them read (not read before the admin sees them)

Access Control (PRD Functional #6)

• A team admin only ever sees redemption notifications for their own team
• A team admin cannot see another team's redemption notifications

Non-Functional

• No new PII beyond what's already visible on /team (redeemer email, course, coupon code)
• Reading /team's notification data is a single query per admin, not a per-coupon loop (verify via code inspection if not observable in UI)
• couponRedemptionNotifications table follows schema conventions: autoincrement integer id, ISO string timestamps, nullable read_at text column (not boolean)

Open Questions needing retroactive confirmation (PRD Open Questions — flagged as needed before implementation, but implementation already shipped)

• Confirm a new purpose-built couponRedemptionNotifications table (vs. generalizing the existing notifications table) is acceptable
• Confirm no retention/cleanup policy for old redemption notifications is acceptable for v1
• Confirm enrollUser's duplicate-enrollment check being a harmless no-op behind redeemCoupon's own earlier check is acceptable (no double-guard issue)