Fix Textual 6.x CSS compatibility: add missing $panel variable

[Copilot]

Textual 6.x's default stylesheet references $panel, causing TUI startup to fail with "reference to undefined variable '$panel'".

Changes

• chatrixcd/tui.py: Added 'panel': theme['surface'] to ChatrixTUI.get_css_variables()
• chatrixcd/tui_turbo.py: Added 'panel': theme['surface'] to ChatrixTurboTUI.get_css_variables()

Maps $panel to existing surface color for consistency across all themes (default, midnight, grayscale, windows31, msdos).

def get_css_variables(self) -> Dict[str, str]:
    theme = self.THEMES.get(self.theme_name, self.THEMES['default'])
    return {
        'primary': theme['primary'],
        'surface': theme['surface'],
        'background': theme['background'],
        'text': theme['text'],
        'text-muted': theme['text-muted'],
        'foreground': theme['text'],
        'panel': theme['surface'],  # Added for Textual 6.x
    }

Resolves startup failures with -t classic and -t turbo flags.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• semaphore.example.test
  • Triggering command: python3 -m unittest discover tests/ -v (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

(ChatrixCD) chatrix-web-sync:/ChatrixCD$ chatrixcd -t classic -N
Error in stylesheet:
/home/chatrix/ChatrixCD/.venv/lib/python3.12/site-packages/textual/app.py, App.DEFAULT_CSS:40:26
╭───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ 38 │ │ Screen.-maximized-view { │
│ 39 │ │ │ layout: vertical !important; │
│ ❱ 40 │ │ │ hatch: right $panel; │
│ 41 │ │ │ overflow-y: auto !important; │
│ 42 │ │ │ align: center middle; │
╰───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯
• reference to undefined variable '$panel'
(ChatrixCD) chatrix-web-sync:/ChatrixCD$ chatrixcd -tturbo -N
Error in stylesheet:
/home/chatrix/ChatrixCD/.venv/lib/python3.12/site-packages/textual/app.py, App.DEFAULT_CSS:40:26
• reference to undefined variable '$panel'

Error in TUI(s)

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

Pull Request Overview

This PR fixes a compatibility issue with Textual 6.x that was causing a stylesheet error when starting the TUI with classic or turbo themes. The fix adds a missing CSS variable mapping.

Key changes:

• Added $panel CSS variable mapping to both TUI implementations for Textual 6.x compatibility
• Updated CHANGELOG.md to document the fix

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
chatrixcd/tui_turbo.py	Added panel CSS variable mapping to surface theme color in get_css_variables()
chatrixcd/tui.py	Added panel CSS variable mapping to surface theme color in get_css_variables()
CHANGELOG.md	Documented the TUI compatibility fix for Textual 6.x