Support ircv3 features

Would be nice if Convos could support some/all of the features listed on https://ircv3.net/irc/. I'm not jumping on this issue though, since libera.chat (my main network) does not support too many features: https://ircv3.net/support/networks#networks-1 There are some test networks though, that I might use to see what to implement.

Probably need to make some new tasks to cover the different features:

- [x] [Capability Negotiation](https://ircv3.net/specs/core/capability-negotiation): CAP, CAP 302, [cap-notify](https://ircv3.net/specs/core/capability-negotiation#cap-notify)
- [x] WebIRC: [WEBIRC](https://ircv3.net/specs/extensions/webirc) - #546
- [ ] Echo Message: [echo-message](https://ircv3.net/specs/extensions/echo-message-3.2)
- [ ] Message IDs: [message-ids](https://ircv3.net/specs/extensions/message-ids), msgid
- [ ] Monitor: [monitor](https://ircv3.net/specs/core/monitor-3.2)
- [ ] Labeled Responses: [labeled-response](https://ircv3.net/specs/extensions/labeled-response)
- [ ] Away Notifications: [away-notify](https://ircv3.net/specs/extensions/away-notify-3.1) - #360
- [ ] [Message Tags](https://ircv3.net/specs/extensions/message-tags)
- [ ] Userhosts in NAMES: [userhost-in-names](https://ircv3.net/specs/extensions/userhost-in-names-3.2)
- [ ] Setname: [setname](https://ircv3.net/specs/extensions/setname)
- [ ] Client-Only Tags: [react](https://ircv3.net/specs/client-tags/react), [reply](https://ircv3.net/specs/client-tags/reply), [typing](https://ircv3.net/specs/client-tags/typing)
- [ ] Multiple Prefixes: [multi-prefix](https://ircv3.net/specs/extensions/multi-prefix-3.1)
- [x] SASL Authentication: SASL v3.1, SASL v3.2, [SNI](https://ircv3.net/specs/core/sni-3.3) #356, [STS](https://ircv3.net/specs/extensions/sts)
- [ ] Invite Notify: [invite-notify](https://ircv3.net/specs/extensions/invite-notify-3.2)
- [ ] Account Tracking: [account-notify](https://ircv3.net/specs/extensions/account-notify-3.1), [account-tag](https://ircv3.net/specs/extensions/account-tag-3.2), [extended-join](https://ircv3.net/specs/extensions/extended-join-3.1)
- [ ] Changing Usernames and Hostnames: [chghost](https://ircv3.net/specs/extensions/chghost-3.2)
- [ ] Server Time: [server-time](https://ircv3.net/specs/extensions/server-time-3.2)
- [ ] Batches: [batch](https://ircv3.net/specs/extensions/batch-3.2)

Start by reviewing the unchecked IRCv3 specifications listed in the issue, such as Echo Message, Message IDs, Monitor, Labeled Responses, and Message Tags. Break the broad request into focused feature tasks, and consider each feature done only when its protocol support is implemented and separately verifiable.

Written by the indexing model from the issue text.