feat(nvim): phase 3 — replace nvim-cmp with blink.cmp and telescope with snacks.picker

Swap the completion engine to blink.cmp v1.x, dropping nvim-cmp,
its eight cmp-* sources, lspkind, and LuaSnip. Swap the picker
to snacks.picker, removing telescope.nvim and six telescope
extensions. LSP capabilities now sourced from blink.cmp; LSP
navigation keymaps and the colorscheme/keymaps/todo pickers move
to Snacks.picker. friendly-snippets is preserved as blink's
snippet source.

lua/absolute/remap.lua

@@ -3,8 +3,10 @@ local opts = {
 	silent = true,
 }
 
-opts.desc = "Show Keymap"
-vim.keymap.set("n", "<leader>?", "<cmd>Telescope keymaps<CR>", opts) -- toggle file explorer
+opts.desc = "Show keymaps"
+vim.keymap.set("n", "<leader>?", function()
+	Snacks.picker.keymaps()
+end, opts)
 
 opts.desc = "Select All"
 vim.keymap.set("n", "<C-a>", "gg0vG$", opts) -- select all