Newsence Core Worker

HTTP endpoints (frontend):
GET  /health
*    /preview                    - Scrape-only
POST /submit                     - Submit URL
POST /embed                      - Generate embeddings
POST /enqueue-user-file          - Kick off workflow for an uploaded user_file (PDF)
POST /rehost-image               - Fetch user-supplied image URL → R2 (SSRF-safe)
GET  /status/:instanceId         - Workflow status (JSON)
GET  /stream/:instanceId         - Workflow status (SSE)

Public media proxy:
GET  /proxy/{options}/{mediaUrl} - Image/video passthrough with edge cache

Admin (X-Internal-Token):
GET  /admin/backfill-signed-urls?table=articles&limit=500 - Re-sign og_image_url rows