post-completion flow: survey, referral program, review ask

- Migration 081: referral_codes, referral_uses, exit_surveys tables
- API: POST /api/v1/survey, POST /api/v1/referral/check, GET /api/v1/referral/:email
- Worker: completion_emails.py — sends completion + 24h follow-up (survey + referral)
- Survey page: /survey/?order=X&rating=N — star rating, feedback, Google review ask
- Referral: REF-FIRSTNAME codes, $25 credit per referred order, no limit
- Low ratings (1-3 stars) trigger Telegram alert for admin follow-up
- Cron: every 15 minutes

api/migrations/081_referral_and_survey.sql

@@ -0,0 +1,47 @@
+-- Referral codes and survey responses for post-completion flow
+
+-- Referral codes (one per customer)
+CREATE TABLE IF NOT EXISTS referral_codes (
+    id SERIAL PRIMARY KEY,
+    code TEXT NOT NULL UNIQUE,            -- e.g. REF-MARKADAMS
+    customer_email TEXT NOT NULL,
+    customer_name TEXT,
+    credit_cents INTEGER DEFAULT 2500,     -- $25 credit
+    times_used INTEGER DEFAULT 0,
+    total_earned_cents INTEGER DEFAULT 0,
+    balance_cents INTEGER DEFAULT 0,       -- unused credit
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_referral_codes_email ON referral_codes(customer_email);
+CREATE INDEX IF NOT EXISTS idx_referral_codes_code ON referral_codes(code);
+
+-- Referral usage tracking
+CREATE TABLE IF NOT EXISTS referral_uses (
+    id SERIAL PRIMARY KEY,
+    referral_code TEXT NOT NULL REFERENCES referral_codes(code),
+    referred_order TEXT NOT NULL,          -- order_number of the new customer's order
+    referred_email TEXT NOT NULL,
+    credit_cents INTEGER DEFAULT 2500,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+-- Exit survey responses
+CREATE TABLE IF NOT EXISTS exit_surveys (
+    id SERIAL PRIMARY KEY,
+    order_number TEXT NOT NULL,
+    customer_email TEXT NOT NULL,
+    rating INTEGER CHECK (rating BETWEEN 1 AND 5),
+    feedback TEXT,
+    would_recommend BOOLEAN,
+    review_link_clicked BOOLEAN DEFAULT FALSE,
+    created_at TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_exit_surveys_order ON exit_surveys(order_number);
+
+-- Track which completion emails have been sent (prevent duplicates)
+ALTER TABLE compliance_orders
+    ADD COLUMN IF NOT EXISTS completion_email_sent_at TIMESTAMPTZ,
+    ADD COLUMN IF NOT EXISTS followup_email_sent_at TIMESTAMPTZ,
+    ADD COLUMN IF NOT EXISTS referral_code TEXT;