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/after/snacks.lua

@@ -0,0 +1,33 @@
+local map = vim.keymap.set
+
+local function with_desc(desc)
+	return { noremap = true, silent = true, desc = desc }
+end
+
+map("n", "<C-p>", function()
+	Snacks.picker.files()
+end, with_desc("Find files"))
+
+map("n", "<leader>gf", function()
+	Snacks.picker.git_files()
+end, with_desc("Find git files"))
+
+map("n", "<leader>pr", function()
+	Snacks.picker.recent()
+end, with_desc("Recent files"))
+
+map("n", "<leader>ps", function()
+	Snacks.picker.grep()
+end, with_desc("Live grep"))
+
+map("n", "<leader>sb", function()
+	Snacks.picker.grep_word()
+end, with_desc("Grep word under cursor"))
+
+map("n", "<leader>pf", function()
+	Snacks.picker.explorer()
+end, with_desc("File explorer (cwd)"))
+
+map("n", "<leader>cf", function()
+	Snacks.picker.explorer({ cwd = vim.fn.expand("%:p:h") })
+end, with_desc("File explorer (current file dir)"))