catppuccin-nvim lualine theme is per-flavor, not 'catppuccin'

In catppuccin-nvim 2.x the lualine theme modules are lualine.themes.catppuccin-mocha (and -latte, -frappe, -macchiato) plus catppuccin-nvim, which follows the active flavour; require('lualine.themes.catppuccin') no longer exists. For custom highlight groups that must match the bar, take colors from require('catppuccin.palettes').get_palette('mocha'): section b uses surface0 and section c uses mantle, or NONE with transparent_background. The theme already ships a terminal mode, so hand-written terminal overrides from other themes can go.