Various static assets served from LMS webapp rather than CDN

Open edX can be configured to load static assets from the URL defined in STATIC_URL_BASE, but not all parts of the system respect this. Instead, some static asset URLs are built as /static/... on the LMS domain. Historically, these were intercepted by the sidecar nginx and served from the staticfiles directory. (TODO: Check how Tutor currently handles this.)

This is an umbrella ticket for tracking down these static files references and changing them to respect STATIC_URL_BASE.

Known examples:

• /static/css/bootstrap/lms-main.css from Learning MFE
  /static/proctoring/templates/student-proctored-exam-attempts-grouped.underscore from instructor dashboard on LMS. May require that static URL base supports CORS headers (same with some fonts).
  /static/dist/openassessment-lms.42bdf01af5d117224bc9.js from an xblock

Start by tracing the listed references: Learning MFE's /static/css/bootstrap/lms-main.css, the instructor dashboard's proctoring template, and the xblock's openassessment JavaScript asset. Check how each constructs URLs relative to STATIC_URL_BASE, and review the sidecar nginx and Tutor note for deployment context. Done means the identified static assets consistently use the configured base and their cross-origin requirements are covered.