docs: add Discord interface documentation - #538

Running Vale across on the following files affected by this PR:

- agent-os/interfaces/overview.mdx
- deploy/interfaces.mdx
- deploy/interfaces/discord/overview.mdx
- production/interfaces/discord.mdx
- production/interfaces/overview.mdx
- agent-os/interfaces/discord/introduction.mdx

Attempting to initialize Vale linter...
Customer vale configuration detected. Attempting to sync packages...
Packages synced successfully.
Attempting to run Vale spellcheck...
Vale spellcheck completed successfully.

agent-os/interfaces/discord/introduction.mdx:
	- 7:187    Did you really mean 'DMs'?

deploy/interfaces/discord/overview.mdx:
	- 6:195    Did you really mean 'DMs'?

examples/agent-os/interfaces/overview.mdx:
	- 8:150    Did you really mean 'ddgs'?
	- 10:4     Did you really mean 'Agui'?


Found 4 suggested changes across 3 files in 4597.98ms