deck-lovers: the projector disconnect survives cancellation, and the deploy script reads .env

deck-lovers’ /ws disconnect cleanup ran unshielded, so a cancelled task could skip telling the audience the projector had left and leave stale clients behind — Starlette’s TestClient cancels the app task right after sending the disconnect, which made the websocket tests hang about four runs in ten. The cleanup is now wrapped in a shielded anyio cancel scope, two test races are gone, and a regression test cancels the handler the way the client does (3c4e938).

Following the deploy preflight added earlier, deploy.sh now reads PORT, PALETTE, FONT, EMOJI, LOGO, FRAME, LOGO_ON, PDF_MODE, PDF_NAME and PDF_QUALITY from .env with flag-over-environment-over-file precedence, parsing the file rather than sourcing it; a local --pdf-only run writes only the named PDF and leaves output/audience.pdf alone. The port check, the .env loader and the audience.pdf copy are covered by a new tests/deploy_test.sh that runs in CI (e45374b).