Use renamed thread titles in notifications

[cocoatoucher]

Notifications currently read the title from the live ACP thread. A user rename is stored as a metadata title override, so the notification can continue to show the original generated title.

This change makes notifications resolve the title from thread metadata first and fall back to the live ACP thread title. The same resolved title is used when the notification opens the thread. A regression test covers a thread with an original generated title and a user-supplied title override.

Validation:

• cargo fmt --all -- --check
• git diff --check
• Attempted cargo test -p agent_ui test_notification_uses_renamed_thread_title; the build exhausted the available local disk space before the agent_ui test binary finished compiling.

Release Notes:

• Fixed agent notifications to show renamed thread titles.

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have @cocoatoucher on file. You can sign our CLA at https://zed.dev/cla. Once you've signed, post a comment here that says '@cla-bot check'.

[cocoatoucher]

@cla-bot check

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have @cocoatoucher on file. You can sign our CLA at https://zed.dev/cla. Once you've signed, post a comment here that says '@cla-bot check'.

[cla-bot]

The cla-bot has been summoned, and re-checked this pull request!

[dinocosta]

Hey @cocoatoucher ! 🙂

Overall the changes seem fine to me but, before we're able to review, we'll need you to sign the CLA.

Also, just double-checking, but have you been able to run your changes and confirm the updated behavior? If so, would you mind sharing a screen recording? I'm asking because of this bit in the Pull Request description which, even though only mentions running the test, I wonder if the same happened when trying to run a development build ▼

Attempted cargo test -p agent_ui test_notification_uses_renamed_thread_title; the build exhausted the available local disk space before the agent_ui test binary finished compiling.

Thanks!