Lets a signed-in user connect their Discord account (OAuth2 identify), storing the
Discord user id that a later feature (DM alerts) will deliver to. Standard
authorization-code flow, all server-side:
- backend/discord_link.py: /discord/link/start redirects to Discord's consent
screen; /discord/link/callback exchanges the code, reads the Discord user id, and
stores it; /discord/unlink forgets it. The `state` is signed with the app auth
secret (stdlib hmac, no new dependency) and carries the Thermograph user id, so a
callback can't be replayed or bound to another account. Every route requires an
active session, so linking acts on whoever is actually logged in.
- models.py: User.discord_id (unique, nullable). schemas.py exposes it on UserRead
so the frontend can show link state.
- app.py: the router under /api/v2/discord.
- account.js: a "Link Discord" / "Unlink Discord" control in the account popover.
- deploy/migrations/001-user-discord-id.sql: the manual column add for the existing
prod accounts DB. This project has no Alembic — create_all only makes missing
tables, so an added column needs a hand-applied migration (documented in-file).
- env example: THERMOGRAPH_DISCORD_CLIENT_SECRET + the redirect to register.
Claude-Session: https://claude.ai/code/session_013dRZmX9D3JEntfMKWMTWZ8
