fix: explicit DoH bypass test at startup

fix: restore downloadImage and complete ytdlp service

fix: bypass restricted DNS via manual DoH resolution

fix: resolve DNS issues by removing force-ipv4

fix: bulletproof direct deno binary install

fix: final network stability and deno path

fix: final network robustness and environment check

fix: resolve DNS hostname error with force-ipv4

fix: global deno install and detailed stderr logging

fix: resolve UID conflict in Dockerfile

fix: add missing YAML metadata to README

deploy: initial backend migration to Hugging Face

initial commit