Implements #16/#17/#36: Founders/Standard/Pro/Business/Backer catalog, Backer email whitelist, prompt-window + token-period gates, and tokens_in/out on conversation/prompt + subscription usage APIs.
## Summary - Companion to [chat_web_app#33](ai_ml_operations/chat_web_app#33) (Account billing + Customer Portal) - Follow-on from finance MVP [#21](#21): add authenticated `POST /api/finance/portal/` that creates a Stripe Billing Portal session and returns `portal_url` - Resolve Stripe customer from the user's latest `Invoice.stripe_customer_id`; return `400` when missing (user must complete Checkout first) - Document `STRIPE_PORTAL_RETURN_URL` (default `{FRONTEND_BASE_URL}/account/`) in settings + env examples ## Test plan - [ ] `manage.py test finance.tests.test_portal finance.tests.test_checkout` - [ ] Authenticated portal create with invoice that has `stripe_customer_id` → `201` + `portal_url` - [ ] No customer / unpaid user → `400` with clear detail - [ ] Missing `STRIPE_SECRET_KEY` → `503` - [ ] Unauthenticated → `401` - [ ] Custom `return_url` in body overrides default portal return URLReviewed-on: #35
## Summary - Closes #21 — new Django `finance` app with Stripe as payment provider - Subscription price defaults to **$10 USD / month** via `SUBSCRIPTION_PRICE_AMOUNT_CENTS = 1000` in `settings.py` (env-overridable) - Persists **Invoice** and **Payment** rows; both registered in Django admin (with payment inline on invoices) - Checkout Session API redirects users to Stripe hosted payment; webhook verifies signatures and upserts ledger idempotently ## API - `POST /api/finance/checkout/` — JWT auth → `{ checkout_url, session_id }` - `GET /api/finance/invoices/` / `GET /api/finance/payments/` — own records - `POST /api/finance/webhooks/stripe/` — Stripe signature-verified webhook ## Config Documented in `.env.example` / `.env.prod.example`: `STRIPE_SECRET_KEY`, `STRIPE_PUBLISHABLE_KEY`, `STRIPE_WEBHOOK_SECRET`, optional `STRIPE_PRICE_ID`, `FRONTEND_BASE_URL` ## Test plan - [x] `uv run python manage.py test finance` (17 tests) - [ ] Set Stripe test keys locally; create checkout session; complete payment in Stripe test mode - [ ] Confirm Invoice/Payment appear in `/admin/` - [ ] Point Stripe webhook to `/api/finance/webhooks/stripe/` and verify `checkout.session.completed` / `invoice.paid`Reviewed-on: #23