compose: Show a first-time banner for jump to sent message conversation.

[prakhar1144]

The first commit is from #29211 pulled here for testing the flow.

Show a one-time banner when jump to sent message conversation takes place for the first time.

Fixes: #29575

Screenshots and screen captures:

Self-review checklist

• Self-reviewed the changes for clarity and maintainability
  (variable names, code reuse, readability, etc.).

Communicate decisions, questions, and potential concerns.

• Explains differences from previous plans (e.g., issue description).
• Highlights technical choices and bugs encountered.
• Calls out remaining decisions and concerns.
• Automated tests verify logic where appropriate.

Individual commits are ready for review (see commit discipline).

• Each commit is a coherent idea.
• Commit message(s) explain reasoning and motivation for changes.

Completed manual review and testing of the following:

• Visual appearance of the changes.
• Responsiveness and internationalization.
• Strings and tooltips.
• End-to-end functionality of buttons, interactions and flows.
• Corner cases, error conditions, and easily imagined bugs.

[zulipbot]

Hello @zulip/design, @zulip/server-onboarding members, this pull request was labeled with the "area: onboarding", "UI experiment" labels, so you may want to check it out!

[alya]

Hm, when I try this from Inbox, it looks like another banner flashes by first. I'm having a hard time capturing it in a screen recording (it's super quick), but maybe you can check in the code whether or not I'm imagining it?

[prakhar1144]

Hm, when I try this from Inbox, it looks like another banner flashes by first. I'm having a hard time capturing it in a screen recording (it's super quick), but maybe you can check in the code whether or not I'm imagining it?

@alya Attaching a video for quick reference of the issue and screenshots to show final behavior:

banner-follow.webm

These message_sent_banners were causing issue:

1. This is no longer needed as sender will be narrowed to that conversation. Removed it.
   

2. "Now Following" - one time banner (When a user automatically follows the topic). The banner will be visible along with the banner we're adding in this PR.

   Banners

   

[alya]

I left a comment in #design.

[alya]

Works for me otherwise!

When there are two banners, they don't appear simultaneously, but I think that's OK.

[prakhar1144]

Updates in the recent push:

• First two commits are from compose_banner: Replace the close button with "Got it" button.  #29910 (Added it here to test collectively)-- Addresses CZO discussion

For @timabbott :

The order in which PRs should be integrated ideally:

1. compose_banner: Replace the close button with "Got it" button.  #29910
2. compose: Jump to conversation where message was sent. #29211
3. This PR

[timabbott]

Merged, thanks @prakhar1144!