Add SNS Marketing Campaign feature

- Add cash_cc_balance to User model (withdrawable CC)
- Create SnsShareSubmission model for SNS share verification
- Add marketing campaign settings to SystemSettings
- Add reward_type to ReferralReward model
- Create /api/sns-share endpoints for submission and verification
- Add referral signup reward logic (10CC on signup)
- Create /sns-share user page for SNS sharing
- Create /admin/sns-shares management page
- Add marketing settings UI to admin settings page
- Add SNS Shares menu to admin sidebar

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

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

backend/migrations/marketing_campaign_v1.sql

@@ -0,0 +1,45 @@
+-- Marketing Campaign Migration V1
+-- Apply to staging/production PostgreSQL databases
+--
+-- Instructions:
+-- 1. Connect to staging: psql -U autonet -d autonet_staging
+-- 2. Run: \i /path/to/marketing_campaign_v1.sql
+--
+
+-- 1. Add cash_cc_balance to users table
+ALTER TABLE users ADD COLUMN IF NOT EXISTS cash_cc_balance FLOAT DEFAULT 0.0;
+
+-- 2. Create sns_share_submissions table
+CREATE TABLE IF NOT EXISTS sns_share_submissions (
+    id SERIAL PRIMARY KEY,
+    user_id INTEGER NOT NULL REFERENCES users(id),
+    car_id INTEGER NOT NULL REFERENCES cars(id),
+    platform VARCHAR(20) NOT NULL,
+    sns_url VARCHAR(500) NOT NULL,
+    status VARCHAR(20) DEFAULT 'pending',
+    rejected_reason TEXT,
+    reward_cc FLOAT DEFAULT 3.0,
+    rewarded_at TIMESTAMP WITH TIME ZONE,
+    submitted_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+    verified_at TIMESTAMP WITH TIME ZONE,
+    verified_by INTEGER REFERENCES users(id)
+);
+
+CREATE INDEX IF NOT EXISTS ix_sns_share_submissions_user_id ON sns_share_submissions(user_id);
+CREATE INDEX IF NOT EXISTS ix_sns_share_submissions_status ON sns_share_submissions(status);
+
+-- 3. Add marketing settings to system_settings table
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS marketing_enabled BOOLEAN DEFAULT FALSE;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS marketing_start_date TIMESTAMP WITH TIME ZONE;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS marketing_end_date TIMESTAMP WITH TIME ZONE;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS sns_share_reward_cc FLOAT DEFAULT 3.0;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS referral_signup_reward_cc FLOAT DEFAULT 10.0;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS event_cc_validity_months INTEGER DEFAULT 6;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS withdrawal_enabled BOOLEAN DEFAULT TRUE;
+ALTER TABLE system_settings ADD COLUMN IF NOT EXISTS min_withdrawal_usd FLOAT DEFAULT 10.0;
+
+-- 4. Add reward_type to referral_rewards table
+ALTER TABLE referral_rewards ADD COLUMN IF NOT EXISTS reward_type VARCHAR(20) DEFAULT 'payment';
+
+-- Done
+SELECT 'Marketing Campaign V1 migration completed!' AS status;