fix(ci): align environment variables with local .env.test to fix 50% E2E failure rate

Root Cause Analysis:
- Local tests: 100% pass rate with USE_MOCK_PURCHASE=true
- CI tests: 50% pass rate WITHOUT USE_MOCK_PURCHASE
- Missing env var caused CI to use REAL database/Stripe instead of mocks

Changes:
- Added USE_MOCK_PURCHASE=true (critical - enables mock purchase service)
- Added NEXT_PUBLIC_USE_MOCK_PURCHASE=true (client-side flag)
- Added PORT=3333 (server port)
- Added BYPASS_UTM_VALIDATION=false (middleware behavior)
- Added NEXT_PUBLIC_FF_PURCHASE_ENABLED=true (feature flag)
- Added NEXT_PUBLIC_ENABLE_TEST_HARNESS=true (test utilities)
- Added NEXT_PUBLIC_TEST_HARNESS_KEY (test auth)
- Added EDGE_CONFIG vars (empty, for AB testing graceful fallback)

Expected Impact:
- 50% → ~100% pass rate in CI
- Aligns CI environment exactly with local .env.test
- Tests will use mock services consistently

Ref: 100% local vs 50% CI = environment mismatch (not test code issue)
Ref: lib/purchase/purchase-service.ts:16-19 (USE_MOCK_PURCHASE check)

Author: mirqtio

.github/workflows/ci-v2.yml

@@ -29,6 +29,7 @@ jobs:
     env:
       NODE_ENV: test
       NEXT_TELEMETRY_DISABLED: '1'
+      PORT: '3333'
       DATABASE_URL: postgresql://postgres:postgres@localhost:5432/anthrasite_test
       DIRECT_URL: postgresql://postgres:postgres@localhost:5432/anthrasite_test
       CI_MOCK_STRIPE: 'true'
@@ -37,6 +38,18 @@ jobs:
       # E2E mode flags
       E2E: '1'
       NEXT_PUBLIC_E2E: 'true'
+      # Mock purchase service (aligns with local .env.test)
+      USE_MOCK_PURCHASE: 'true'
+      NEXT_PUBLIC_USE_MOCK_PURCHASE: 'true'
+      BYPASS_UTM_VALIDATION: 'false'
+      # Feature flags
+      NEXT_PUBLIC_FF_PURCHASE_ENABLED: 'true'
+      # Test harness
+      NEXT_PUBLIC_ENABLE_TEST_HARNESS: 'true'
+      NEXT_PUBLIC_TEST_HARNESS_KEY: 'test-key-12345'
+      # Edge config (empty for tests)
+      EDGE_CONFIG: ''
+      EDGE_CONFIG_BASE64_KEY: ''
       # Stripe test keys
       STRIPE_SECRET_KEY: ${{ secrets.STRIPE_SECRET_KEY }}
       NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY: ${{ secrets.NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY }}