Draft: Fix ftb discovery popover not showing up

What does this MR do and why?

this mr fixes the issue that file tree browser discovery popover is not showing up.

Technical details

"i thought this would be an easy fix, chao"

this fix turns out to be a lot more involved than expected ™️ travelling through the commits in repository/file_tree_browser/components/file_tree_browser_toggle.vue, i don't know if this ever works as the requirements in #569265 (closed) and #560578 (closed) 🌚 there is no screenshots in Resolve "Fix file tree browser popover interact... (!207309 - merged) to verify. so i went ahead basically redid the whole thing.

"so what did you changed, chao"

• add back id on the toggle button, which got removed by me in 4522dc4e
• remove .file-tree-browser-toggle-wrapper. it's stopping the popover from showing up at the correct space
• remove the logic to hide popover when toggle button is clicked. use @hidden event instead
• update to triggers to manual
• update variable names so they're more representative of what they do
• simplified some logic with v-model and etc
• move all the logic out of file_tree_browser_toggle.vue into its own file
• call that file from header_area, since we only need to show the popover when the file tree browser is closed

References

discovered during team test session #582189 (comment 2927752158)

Screenshots or screen recordings

CleanShot 2025-12-03 at 22.25.33.mp4

How to set up and validate locally

• enable repository_file_tree_browser feature flag
• make sure you are logged in on GDK. the popover will only display if you are logged in.
• go to the repository view, click on any folders/files (note, this won't show on project overview page)
• popover should show
• close the popover with x button, popover should disappear and not reappear on page refresh
• open browser devtool (i.e. Chrome right click "Inspect") > Application tab > Storage section > Local storage, search for ftb, delete ftb-popover-dismissed entry or update the value to false
• refresh the page, popover should show again,
• expand the file tree browse, popover should disappear and does not reappear on page refresh

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Resolves #582974