feat: initial commit — backend API + student cabinet frontend

- Go backend: auth (JWT), points earn/spend, QR token generation,
  partners, admin grant/stats endpoints with chi router
- Next.js 14 frontend: login, student dashboard, transaction history,
  QR display, partners list
- PostgreSQL migrations (4 tables), Redis cache, Docker Compose
- CORS middleware, role-based route protection, Zustand auth store

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

migrations/00002_init_partners.sql

@@ -0,0 +1,17 @@
+-- +goose Up
+CREATE TABLE partners (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    -- user_id references the cashier/partner account in users table
+    user_id         UUID REFERENCES users(id) ON DELETE SET NULL,
+    name            TEXT NOT NULL,
+    address         TEXT NOT NULL,
+    -- max_spend_pct: maximum percentage of a purchase total that can be paid with points
+    max_spend_pct   INTEGER NOT NULL DEFAULT 50 CHECK (max_spend_pct BETWEEN 1 AND 100),
+    is_active       BOOLEAN NOT NULL DEFAULT TRUE,
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX ON partners(is_active);
+
+-- +goose Down
+DROP TABLE IF EXISTS partners;