feat(phase-6): rich super admin dashboard UI

Full DashboardPage rewrite with:
- 5-KPI row (total/active schools, expiring licenses, open tickets, SMS today)
- 30-day SMS volume bar chart (reuses SmsPage chart pattern)
- Revenue snapshot: MRR, paid this month, outstanding + overdue invoices
- School health table: status, tier, credit balance with LOW badge, license
  expiry countdown, last-seen relative time — sortable + search + status filter
- Quick actions panel with open-ticket badge counter
- Mini stats: SMS queue depth, suspended school count
- Refresh button with last-updated timestamp
- api.ts: getDashboardSchoolHealth + getDashboardRevenue

.paul/phases/06-super-admin-dashboard/README.md

@@ -1,9 +1,29 @@
 # Phase 06: Super Admin Dashboard UI
 
-**Status:** Not started
+**Status:** Complete
+**Completed:** 2026-03-16
 
 ## Goal
-Rich dashboard with KPI cards, school health table, SMS volume chart, revenue snapshot.
 
-## Plans
-- [ ] TBD — run /paul:plan when Phase 5 is complete
+Replace the minimal DashboardPage skeleton with a rich, data-driven super admin dashboard.
+
+## What was built
+
+### Backend (already existed from Phase 1/4 scaffolding)
+- `GET /api/dashboard/summary` — KPI counts
+- `GET /api/dashboard/school-health` — school list with license/credit health
+- `GET /api/dashboard/revenue` — MRR, outstanding, overdue, paid this month
+
+### Frontend — DashboardPage.vue (full rewrite)
+
+1. **KPI row (5 cards):** Total Schools, Active, Expiring Licenses, Open Tickets, SMS Today
+2. **School Health Table:** name, status badge, tier, SMS credits (with low-credit warning), license expiry countdown, last seen timestamp — sortable columns, status filter, search
+3. **SMS Volume Chart:** 30-day bar chart (sent/failed), reused from SmsPage pattern
+4. **Revenue Snapshot panel:** MRR, Paid This Month, Outstanding (count), Overdue (count + red highlight)
+5. **Quick Actions:** Add School (→ /schools), SMS Gateway (→ /sms), Billing (→ /billing)
+6. **Refresh button** with last-updated timestamp
+
+### api.ts additions
+- `getDashboardSchoolHealth(params)` — calls `/dashboard/school-health`
+- `getDashboardRevenue()` — calls `/dashboard/revenue`
+- `getDashboardSmsChart()` — calls `/sms/stats?days=30` (reuse existing)