fix(themes): complete summer-day with Everforest Light palette

colors.toml and icons.theme were copy-pasted from summer-night (a dark
theme). Repalette to Everforest Light, mark as light via light.mode,
switch icons to Yaru-blue, fix the broken Waybar import, and add the
btop/neovim/vscode/rofi/walker app configs the sibling themes ship.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

themes/palettes/summer-day/apps/neovim.lua

@@ -0,0 +1,16 @@
+return {
+	{ "neanias/everforest-nvim" },
+	{
+		"LazyVim/LazyVim",
+		opts = {
+			colorscheme = "everforest",
+			background = "soft",
+		},
+	},
+	{
+		"LazyVim/LazyVim",
+		init = function()
+			vim.opt.background = "light"
+		end,
+	},
+}