Document Backblaze keys in the droplet env file

Add "Load from Backblaze" pickers for turns/captions and text input

Point at Orchestrator's new self-service allowlist admin panel

Rewrite docs for terser, more austere style (no content changes)

Document the REST API and the security model

Add async REST job API alongside the existing Gradio UI

Document container egress restrictions and second-pass security gaps

Document HF_TOKEN over-scoping as a known gap (security review)

Add docs/ covering configuration, storage, deployment, and operations