Implement OTP-based email verification system

Add custom email verification using 6-digit OTP codes via Mailketing API:

Database:
- Create auth_otps table with 15-minute expiry
- Add indexes and RLS policies for security
- Add cleanup function for expired tokens
- Insert default auth_email_verification template

Edge Functions:
- send-auth-otp: Generate OTP, store in DB, send via Mailketing
- verify-auth-otp: Validate OTP, confirm email in Supabase Auth

Frontend:
- Add OTP input state to auth page
- Implement send/verify OTP in useAuth hook
- Add resend countdown timer (60 seconds)
- Update auth flow: signup → OTP verification → login

Features:
- Instant email delivery (no queue/cron)
- 6-digit OTP with 15-minute expiry
- Resend OTP with cooldown
- Admin-configurable email templates
- Indonesian UI text

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

supabase/migrations/20250102000001_auth_otp.sql

@@ -0,0 +1,68 @@
+-- ============================================================================
+-- Auth OTP System - Email Verification with One-Time Passwords
+-- ============================================================================
+
+-- Create auth_otps table to store OTP codes for email verification
+CREATE TABLE IF NOT EXISTS auth_otps (
+  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+  user_id UUID NOT NULL REFERENCES auth.users(id) ON DELETE CASCADE,
+  email TEXT NOT NULL,
+  otp_code TEXT NOT NULL,
+  expires_at TIMESTAMP WITH TIME ZONE NOT NULL,
+  used_at TIMESTAMP WITH TIME ZONE,
+  created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+);
+
+-- Create indexes for performance
+CREATE INDEX IF NOT EXISTS idx_auth_otps_user_otp ON auth_otps(user_id, otp_code);
+CREATE INDEX IF NOT EXISTS idx_auth_otps_expires_at ON auth_otps(expires_at);
+CREATE INDEX IF NOT EXISTS idx_auth_otps_email ON auth_otps(email);
+
+-- Enable RLS
+ALTER TABLE auth_otps ENABLE ROW LEVEL SECURITY;
+
+-- RLS Policies
+-- Service role has full access
+CREATE POLICY "Service role can do everything" ON auth_otps
+  FOR ALL
+  TO service_role
+  USING (true)
+  WITH CHECK (true);
+
+-- Authenticated users can query their own OTPs
+CREATE POLICY "Users can view own OTPs" ON auth_otps
+  FOR SELECT
+  TO authenticated
+  USING (auth.uid() = user_id);
+
+-- Edge functions (via service role) can insert OTPs
+CREATE POLICY "Service role can insert OTPs" ON auth_otps
+  FOR INSERT
+  TO service_role
+  WITH CHECK (true);
+
+-- Edge functions (via service role) can update OTPs (mark as used)
+CREATE POLICY "Service role can update OTPs" ON auth_otps
+  FOR UPDATE
+  TO service_role
+  USING (true)
+  WITH CHECK (true);
+
+-- Function to clean up expired OTPs
+CREATE OR REPLACE FUNCTION cleanup_expired_otps()
+RETURNS void AS $$
+BEGIN
+  DELETE FROM auth_otps
+  WHERE expires_at < NOW();
+END;
+$$ LANGUAGE plpgsql;
+
+-- Comment on table
+COMMENT ON TABLE auth_otps IS 'Stores OTP codes for email verification. Generated when users register, used to confirm email addresses.';
+
+-- Comment on columns
+COMMENT ON COLUMN auth_otps.user_id IS 'Reference to auth.users.id';
+COMMENT ON COLUMN auth_otps.email IS 'Email address being verified (for redundancy)';
+COMMENT ON COLUMN auth_otps.otp_code IS '6-digit OTP code';
+COMMENT ON COLUMN auth_otps.expires_at IS 'OTP expiration time (typically 15 minutes)';
+COMMENT ON COLUMN auth_otps.used_at IS 'When OTP was used (NULL if unused)';