Adds an optional daily Discord post of the day's most anomalous cities, built from
the same data/homepage.json feed the homepage renders — so the post and the site
always agree. Delivery is a single incoming-webhook POST (no bot, no gateway, no
new process): it rides the notifier daemon like the feed refresh does, once per
day after the refresh, leader-only. With no webhook configured it no-ops.
- backend/discord.py: build_embed() renders the top cities as a rich embed (each
line: city, reading in °F and °C, the normal for context, percentile + grade;
non-today readings are dated). post_daily_feed() is best-effort — it skips a
stale/empty feed and never raises, so a Discord failure can't disturb a pass.
- notify.py: a once-a-day guard (_maybe_post_discord) beside the homepage-refresh
guard; only marks the day done once a post lands, so a transient failure retries.
- deploy/thermograph.env.example: THERMOGRAPH_DISCORD_WEBHOOK (the URL is the
credential — env only).
The webhook value is the top anomaly's tail for the accent colour and reuses the
feed's build time as the embed timestamp. httpx (already a dependency) does the POST.
Claude-Session: https://claude.ai/code/session_013dRZmX9D3JEntfMKWMTWZ8
6726544b56