luci-app-filemanager: auto sizing for file-list, dark mode support, other minor fixes

[ghost]

Pull Request details

Description

• Automatic width and height for the file-list window, automatic width for text editor, hex editor and help windows. Justification is that user can adjust width using browser window and allows responsive width to function. Removal of width user settings.
• Added support for dark mode, previously was hard-coded for light mode and caused a conflict with using bootstrap which adapts to both modes.
• Minor fixes to buttons, heading, nav bar, borders. Small style tidying, including:
  • File list shows alternating background colour on rows.
  • File Manager title no longer accidentally line-breaks.
  • Path bar now fluid.
  • Borders all fixed, parent directory table row resolved.
  • Tab buttons refined further.
  • Go button now a right arrow, to simplify use and reduce the need for translation.
• Tested across all luci-themes, as a result:
  • Added fallback CSS if a theme does not have dark mode.
  • Enclosed most open CSS classes as it was affecting other elements outside of the file manager.
• Closes luci-app-filemanager: flexible width, dark mode, refinements #8537, although I could not figure out how to automatically set file uploads' permissions from 600 to 644 automatically.

Video

luci.mp4

Screenshots

Maintainer (Preferred)

Dmitry R, but I can't seem to find a GitHub account.
Pinging @systemcrash due to recent commits.

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Tested on

OpenWrt version: OpenWrt 25.12.2 (r32802-f505120278)
LuCI version: LuCI openwrt-25.12 branch (26.100.49936~3cefdb7)
Web browser: Safari Version 26.5 (21624.2.2)

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Checklist

• This PR is not from my main or master branch 💩, but a separate branch. ✅
• Each commit has a valid ✒️ Signed-off-by: <my@email.address> row (via git commit --signoff).
• Each commit and PR title has a valid 📝 <package name>: title first line subject for packages.
• (Optional) Includes what Issue it closes (e.g. openwrt/luci#issue-number).