refactor(nvim): modernize plugin stack

Removed dead weight:
- Drop nightfox, rose-pine, kanagawa, everforest colorschemes
- Remove fzf/fzf.vim (redundant with telescope)
- Remove vim-fugitive and its keymaps (lazygit covers this)
- Remove Comment.nvim (built into nvim 0.10+)

Replaced:
- nvim-cmp → blink.cmp (Rust-powered, faster, ghost text)
- none-ls/null-ls → conform.nvim (async, maintained)
- cmp-nvim-lsp capabilities → blink.cmp.get_lsp_capabilities()
- Copilot suggestions now routed through blink-copilot

Added:
- lazydev.nvim for proper Lua LSP in nvim config
- flash.nvim (s/S jump anywhere on screen)
- which-key.nvim (leader key popup with groups)
- snacks.nvim (notifier + word highlights)
- nvim-treesitter-textobjects (af/if, ac/ic, ]f/[f)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nvim/lua/plugins/prettier.lua

@@ -1,28 +1,29 @@
 return {
-  "nvimtools/none-ls.nvim",
-  dependencies = { "nvim-lua/plenary.nvim" },
-  config = function()
-    local null_ls = require("null-ls")
-    null_ls.setup({
-      debug = false,
-      sources = {
-        -- null_ls.builtins.diagnostics.markdownlint.with({
-        --   filetypes = { "markdown", "markdown.pandoc", "pandoc" },
-        -- }),
-        null_ls.builtins.formatting.prettier.with({
-          filetypes = { "markdown", "markdown.pandoc", "pandoc" },
-        }),
-      },
-      on_attach = function(client, bufnr)
-        if client.supports_method("textDocument/formatting") then
-          vim.api.nvim_create_autocmd("BufWritePre", {
-            buffer = bufnr,
-            callback = function()
-              vim.lsp.buf.format({ bufnr = bufnr })
-            end,
-          })
-        end
-      end,
-    })
-  end,
-}
+  "stevearc/conform.nvim",
+  event = { "BufWritePre" },
+  cmd = { "ConformInfo" },
+  keys = {
+    {
+      "<leader>fm",
+      function() require("conform").format({ async = true }) end,
+      desc = "Format buffer",
+    },
+  },
+  opts = {
+    formatters_by_ft = {
+      javascript      = { "prettier" },
+      typescript      = { "prettier" },
+      javascriptreact = { "prettier" },
+      typescriptreact = { "prettier" },
+      json            = { "prettier" },
+      html            = { "prettier" },
+      css             = { "prettier" },
+      markdown        = { "prettier" },
+      yaml            = { "prettier" },
+    },
+    format_on_save = {
+      timeout_ms = 500,
+      lsp_fallback = true,
+    },
+  },
+}