feat: VSCode 风格 Neovim 配置

- 分层架构：config/{options,keymaps,lazy} + plugins/
- 保留：blink.cmp, oil.nvim, runner.lua, cmake-tools, diffview, tokyonight
- 新增 UI：bufferline, lualine, noice, nvim-notify, dashboard, dressing
- 新增编辑器：Comment, nvim-surround, vim-illuminate, toggleterm, flash
- 新增视觉：indent-blankline, nvim-ufo, rainbow-delimiters
- 新增 Git：lazygit 集成
- 新增 DAP：persistent-breakpoints, nvim-dap-virtual-text
- 修复：which-key 启用, rustaceanvim 填充, 键位冲突解决
- 语法检查：22/22 文件全部通过 luajit -b

lua/plugins/treesitter.lua

@@ -0,0 +1,24 @@
+-- =============================================================================
+-- treesitter.lua — 语法高亮
+-- =============================================================================
+-- 【保留】你的完整 ensure_installed 列表。
+-- 【新增】✅ fold 配置让 nvim-ufo 可以使用 treesitter 折叠。
+
+return {
+  {
+    "nvim-treesitter/nvim-treesitter",
+    event = { "BufReadPre", "BufNewFile" },
+    build = ":TSUpdate",
+    opts = {
+      ensure_installed = {
+        "lua", "bash", "rust", "c", "cpp", "cmake",
+        "python", "java", "go", "json", "toml",
+        "markdown", "regex", "vim",
+      },
+      highlight = { enable = true },
+      indent    = { enable = true },
+      -- ✅ 新增：启用 treesitter 折叠（nvim-ufo 依赖）
+      fold = { enable = true },
+    },
+  },
+}