[Bug]: Headerbar conditions regression

[IBBoard]

Describe the bug

#575 has come back - Tuba isn't showing the view switcher at narrow-but-not-narrow-enough-to-put-the-buttons-at-the-bottom sizes. It appears to be due to #651 fixing race conditions but breaking the initial value.

Steps To Reproduce

1. Open Tuba with a default width of 555px

• Expected: Title bar contains view switcher
• Actual: Title bar contains title.

1. Resize Tuba below 550px
2. Resize Tuba above 550px
3. View switcher is shown

Logs and/or Screenshots

No response

Instance Backend

Mastodon

Operating System

openSuse Tumbleweed

Package

Compiled manually

Troubleshooting information

os: openSUSE Tumbleweed (null)
prefix: /usr
flatpak: false
version: -6793a3c (development)
gtk: 4.12.4 (4.12.4)
libadwaita: 1.4.2 (1.4.2)
libsoup: 3.4.4 (3.4.4)
libgtksourceview: 5.10.0 (5.10.0)

Additional Context

Built 8038e8f - broken.
Built 6793a3c (previous commit, before #651 merged) - correct behaviour.
Tried manually adding some of the old hooks back without any luck.
Added info() calls to TabbedBaseView.title_stack_page_visible but it doesn't log until the resize. So the breakpoint appears not to be handling the default size?