fix(db): add missing ai_credit_orders columns + ai_coupons tables

20260814000000: add coupon_code + discount_applied to ai_credit_orders
CREATE TABLE — create_order inserts both columns but the original
migration omitted them.

20260814020000 (new): create ai_coupons + ai_coupon_redemptions, the
tables referenced by create_order/verify_order in ai_credits.rs.
Extracted from the skipped 20260706300000 migration which couldn't be
enabled because it referenced ai_credit_orders before that table existed.

Runbook updated with the 3 pending prod migrations and redeploy step.

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

crates/db/migrations/20260814000000_fix_ai_credit_packages_pricing_and_orders.up.sql

@@ -38,6 +38,8 @@ CREATE TABLE IF NOT EXISTS ai_credit_orders (
     amount_inr INT NOT NULL, -- paise
     credits INT NOT NULL,
     status VARCHAR(20) NOT NULL DEFAULT 'PENDING', -- PENDING, SUCCESS, FAILED
+    coupon_code VARCHAR(100),
+    discount_applied INT NOT NULL DEFAULT 0, -- paise
     verified_at TIMESTAMPTZ,
     created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );

crates/db/migrations/20260814020000_ai_coupons.down.sql

@@ -0,0 +1,8 @@
+BEGIN;
+DROP INDEX IF EXISTS idx_ai_coupon_redemptions_coupon;
+DROP INDEX IF EXISTS idx_ai_coupon_redemptions_user;
+DROP INDEX IF EXISTS idx_ai_coupons_valid;
+DROP INDEX IF EXISTS idx_ai_coupons_code;
+DROP TABLE IF EXISTS ai_coupon_redemptions;
+DROP TABLE IF EXISTS ai_coupons;
+COMMIT;

crates/db/migrations/20260814020000_ai_coupons.up.sql

@@ -0,0 +1,63 @@
+-- AI credit coupon tables, extracted from the skipped
+-- 20260706300000_ai_coupons_promotions.up.sql.skip which could not be
+-- enabled because it referenced ai_credit_orders before that table
+-- existed (it ran before 20260814000000 chronologically).
+--
+-- Only the tables actually used by apps/payments/src/ai_credits.rs are
+-- created here (ai_coupons + ai_coupon_redemptions). The broader
+-- promotions/referral tables from the original skip file are deferred.
+
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS ai_coupons (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    code VARCHAR(100) UNIQUE NOT NULL,
+    name VARCHAR(200) NOT NULL,
+    description TEXT,
+
+    -- Discount configuration
+    discount_type VARCHAR(20) NOT NULL CHECK (discount_type IN ('percentage', 'fixed_amount')),
+    discount_value NUMERIC(10, 2) NOT NULL CHECK (discount_value >= 0),
+
+    -- Applicability
+    applicable_package_ids UUID[] DEFAULT '{}',
+    min_purchase_amount NUMERIC(12, 2),
+    max_discount_amount NUMERIC(12, 2),
+
+    -- Limits
+    max_redemptions INT NOT NULL DEFAULT 1,
+    redemptions_used INT NOT NULL DEFAULT 0,
+    max_redemptions_per_user INT DEFAULT 1,
+
+    -- Validity
+    valid_from TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    valid_until TIMESTAMPTZ,
+
+    -- Status
+    is_active BOOLEAN NOT NULL DEFAULT TRUE,
+
+    -- Audit
+    created_by UUID REFERENCES users(id),
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS ai_coupon_redemptions (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    coupon_id UUID NOT NULL REFERENCES ai_coupons(id) ON DELETE CASCADE,
+    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    order_id UUID REFERENCES ai_credit_orders(id),
+    credits_purchased INT NOT NULL,
+    discount_applied NUMERIC(12, 2) NOT NULL,
+    final_amount_paid NUMERIC(12, 2) NOT NULL,
+    redeemed_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+
+    UNIQUE(coupon_id, user_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_ai_coupons_code ON ai_coupons(code) WHERE is_active = TRUE;
+CREATE INDEX IF NOT EXISTS idx_ai_coupons_valid ON ai_coupons(valid_from, valid_until) WHERE is_active = TRUE;
+CREATE INDEX IF NOT EXISTS idx_ai_coupon_redemptions_user ON ai_coupon_redemptions(user_id);
+CREATE INDEX IF NOT EXISTS idx_ai_coupon_redemptions_coupon ON ai_coupon_redemptions(coupon_id);
+
+COMMIT;

docs/LIVE_SERVER_RUNBOOK.md

@@ -20,6 +20,38 @@ All four DB tasks below are done and confirmed against the live production DB.
 
 ---
 
+## ⏳ Pending — DB migrations for AI credit purchases (2026-08-14)
+
+Three new migrations need to be applied to prod. Run **in order** (sqlx-migrate handles this, but listed explicitly so you can verify):
+
+```bash
+# On the live server, inside nxtgauge-backend-rust:
+git pull origin high-performance
+sqlx migrate run --database-url "$DATABASE_URL"
+```
+
+That single command applies all three in chronological order. Verify after:
+
+```bash
+sqlx migrate info --database-url "$DATABASE_URL"
+```
+
+All three should show `applied`.
+
+| Migration | What | Why |
+|---|---|---|
+| `20260814000000_fix_ai_credit_packages_pricing_and_orders.up.sql` | Fixes prices (99→9900 paise etc.) + creates `ai_credit_orders` with `coupon_code` + `discount_applied` columns | AI credit purchase flow was completely broken: no orders table, wrong prices |
+| `20260814010000_ai_credit_packages_role_scoping.up.sql` | Adds `applicable_roles TEXT[]` column to `ai_credit_packages` | Admin UI now supports restricting packages to specific roles |
+| `20260814020000_ai_coupons.up.sql` | Creates `ai_coupons` + `ai_coupon_redemptions` tables | Backend `create_order`/`verify_order` reference these tables |
+
+After applying, redeploy the payments service:
+
+```bash
+systemctl restart nxtgauge-payments
+```
+
+---
+
 ## 1. Deploy backend changes
 
 ```bash