feat: add partner interface, admin dashboard, and unit tests

Partner flow: QR scanner component (html5-qrcode) with camera
permission/not-found handling, 3-step spend flow (scan → amount
entry with auto-filled max → success/error result).

Admin dashboard: stats overview, grant points with debounced
student search, paginated transactions table with type filters,
paginated students table.

Tests: comprehensive unit tests for points and auth packages —
service (all paths including error branches, RS256 wrong-method),
handler (all HTTP status codes via httptest), JWT round-trip,
repository constructors. Auth coverage: 72.9%, points service
coverage: 100%.

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

frontend/package.json

@@ -9,6 +9,7 @@
     "lint": "next lint"
   },
   "dependencies": {
+    "html5-qrcode": "^2.3.8",
     "next": "14.2.35",
     "qrcode.react": "^4.2.0",
     "react": "^18",