Decision #1: watch the real Discord screen share by running a real web client
under a virtual display (Xvfb) and capturing rendered frames — not bot/selfbot
protocol receive. PLAN.md records all locked decisions and the step list.
PoC (poc/capture_xvfb.py + test_page.html) launches system Chrome non-headless
under Xvfb via Playwright and captures 6 changing, non-blank frames -> de-risks
the display+capture chain on the .9 host.
