Add Render yt-dlp proxy service, update HF downloader to stream from it

Fix: Use COBALT_INSTANCE_URL env var for self-hosted Cobalt on Render

Debug: Test actual HTTP connectivity to candidate instances in health endpoint

Fix: Use only HF-resolvable instances (cobalt.privacyredirect.com + Invidious fallback)

Debug: Add DNS resolution check for Cobalt/Invidious instances to health endpoint

Fix: Switch to Cobalt v10 community instances (YouTube DNS blocked on HF)

Fix: Force IPv4 in yt-dlp, add YouTube DNS check to health endpoint

Fix: Force Docker cache bust to deploy new downloader

Refactor: Remove Cobalt fallback, use yt-dlp with cookies only

Security: Load cookies from YT_COOKIES_B64 secret at startup, remove from repo

Fix: Correct cookies path to /home/user/app/cookies.txt for HuggingFace

Fix: Use yt-dlp with cookies as primary downloader, Cobalt as fallback

Fix: Switch to Cobalt API to bypass bot blocks

Fix: Add nodejs as JS runtime for yt-dlp

Fix: Better logging and latest dependencies for yt-dlp impersonation

Fix: Add curl-cffi and use chrome impersonation in yt-dlp to bypass bot detection without proxies

Fix: Replace yt-dlp with Cobalt Proxy API to bypass server blocks

Enhance: Support cookies.txt for bypassing bot detection

Fix: Spoof mobile clients to bypass YouTube bot detection

Fix: Socket monkey-patch for YouTube IP resolution bypass

Fix: Bypass system DNS using dnspython (Manual IP resolution)

Fix: Overhaul to Bullseye base + yt-dlp Python API

Fix: Hardcore DNS bypass using aria2c with Google DNS

Fix: Bypassing YouTube download blocks (UserAgent + IPv4)

Fix: Add ca-certificates and DNS health check

Initial ClipForge API deployment