Store API keys and secrets encrypted in the SQLite database via the
existing Vault module (AES-256-GCM). The only external dependency is
SECRET_KEY_BASE — everything else lives in the portable DB file.
- Add encrypted_value column to settings table with new "encrypted" type
- Add put_secret/get_secret/delete_setting/secret_hint to Settings context
- Add Secrets module to load encrypted config into Application env at startup
- Add Stripe.Setup module with connect/disconnect/verify_api_key flow
- Auto-creates webhook endpoints via Stripe API in production
- Detects localhost and shows Stripe CLI instructions for dev
- Add admin credentials page at /admin/settings with guided setup:
- Not configured: single Secret key input with dashboard link
- Connected (production): status display, webhook info, disconnect
- Connected (dev): Stripe CLI instructions, manual signing secret input
- Remove Stripe env vars from dev.exs and runtime.exs
- Fix CSSCache test startup crash (handle_continue instead of init)
- Add nav link for Credentials page
507 tests, 0 failures.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>