Replace every occurrence of "RBox" with "MyWebdav" in source files, configuration,
legal documents, UI components, and test fixtures. This includes renaming the
`RBoxApp` class to `MyWebdavApp` in the JavaScript component, updating the
TOTP issuer from "RBox" to "MyWebdav" in the auth router, changing the
application description in the argument parser, and updating all user-facing
strings in HTML templates, legal policies, and the manifest file. The
`.env.example` default for `TOTP_ISSUER` is also updated accordingly.
Add composite index on usage_records for user_id, record_type, and timestamp columns; add individual indexes on record_type, timestamp, period_start, and status fields in billing models. Implement lazy Stripe API key initialization via _ensure_api_key method called before each Stripe operation. Fix monthly usage query to use date range filtering instead of year/month decomposition. Refactor auth login endpoint to replace OAuth2PasswordRequestForm dependency with custom LoginRequest model. Add error handling wrapper around current usage endpoint and introduce loading/error CSS classes for billing UI. Convert code editor view from absolute positioning to fixed overlay with centered modal container. Include Stripe.js script tag in index.html and add new APIContract class for response validation against schemas.
