Add LibreWolf template (userChrome.css / userContent.css) using the Noctalia palette

[venus-fire]

Template

• App: LibreWolf
• Template id (directory): librewolf
• New template

What it themes

LibreWolf is a Firefox fork, so this is the same CSS as the firefox/ template
(native userChrome.css / userContent.css), adapted to LibreWolf's profile
locations:

• librewolf-userChrome.css — tab bar, navigation toolbar, URL bar + results,
  bookmarks bar, sidebar, find bar, menus/panels, context menus, dialogs,
  autocomplete popups, download panel, web select dropdowns.
• librewolf-userContent.css — about:newtab/home, about:preferences and
  its sub-dialogs, about:addons, about:logins, about:protections,
  about:config, about:profiles, etc.

Dark and light variants are generated; the browser switches via
prefers-color-scheme. No extension required.

Testing

Tested as a user template (Noctalia v5.0.0), applied via
noctalia msg templates-apply.

• App version tested: LibreWolf (current release, Firefox 153-era engine;
  profile under ~/.config/librewolf/librewolf/)
• Applied a dark theme and confirmed the app picked it up (screenshots below)
• Applied a light theme and confirmed the app picked it up
• Re-applied twice and the app config is still correct (hooks are idempotent)

Screenshots

Hooks

• What the hook does: finds LibreWolf profiles by locating prefs.js
  (~/.librewolf, $XDG_CONFIG_HOME/librewolf including the doubled
  librewolf/librewolf/ layout, Flatpak, Snap), creates the profile chrome/
  dir, adds the Noctalia @import lines to userChrome.css/userContent.css,
  and enables toolkit.legacyUserProfileCustomizations.stylesheets,
  svg.context-properties.content.enabled and devtools.chrome.enabled
  through the profile's user.js.
• It is idempotent: running it twice does not duplicate lines or corrupt the config.
• It fails loudly (non-zero exit, message on stderr) when the app's config is missing.
• It downloads nothing and executes nothing it did not ship in this directory.
• It touches only this app's own config.

Checklist

• The directory name matches the [catalog.librewolf] id in template.toml.
• category is one of: ai, audio, browser, chat, compositor, editor, gaming, launcher, system, terminal, misc.
• Every input_path names a file that exists in this directory.
• No generated output or app-specific personal config is committed.