feat: support toast notifications via pruneNotificationType

[essinghigh]

Closes #319

This PR introduces pruneNotificationType as a new configuration option, allowing users to choose between chat and toast for prune notifications.

Changes
dcp.schema.json / lib/config,ts

• Added pruneNotificationType config option with "chat" (default) or "toast"

lib/ui/notifications.ts

• Added helper functions to handle truncation (showDistillation, showCompression summary & line length)
• Updated sendUnifiedNotification and sendCompressNotification to display toasts when configured to do so

---

Reopened from #321. Reimplementing this from dev gave me enough headache (my own fault!) to realize I'd over-engineered this the first time around. This is a much simpler approach and provides the same functionality. Also renamed the config option to fit with the others, thought it was a little out of place as just notificationType.

Let me know what you think.

---

Screenshots

Detailed:

Minimal:

Truncating:

[Tarquinen]

Hell yea this looks awesome! Sorry again about the git mess I made earlier. Let me know if you have any more cool ideas like this. Think you just need to run a format and we're good to go

[essinghigh]

Forgot to run prettier before pushing this, should be good now.
All good r.e. the git changes, it gave me a good opportunity to look over what I'd done and reimplement it much cleaner.

[Tarquinen]

Might be a few days before dev is merged into master and released, there's a lot of other changes that i'm still testing and that are still being worked on. I'll probably push a beta version tonight though that will have this in it. Thanks for your help!