refactor(nvim): 完整重写配置，支持 Go/Rust/Python/TypeScript 开发

- 架构重构：新增 plugins/lang/ 子目录，按语言拆分配置
- 补全引擎：nvim-cmp → blink.cmp + LuaSnip
- 文件浏览：新增 neo-tree（<Space>e）
- 语言支持：
  - Go: ray-x/go.nvim + dap-go + neotest-go
  - Rust: rustaceanvim + crates.nvim
  - Python: venv-selector + dap-python + neotest-python
  - TypeScript: typescript-tools.nvim（替换 ts_ls）
- LSP: lazydev + mason + mason-lspconfig + fidget + inc-rename
- 格式化: conform.nvim（lsp_format fallback，保存时自动格式化）
- Lint: nvim-lint（selene 替换 luacheck，Mason 可直接安装）
- UI: snacks.nvim（dashboard+notifier+picker）+ noice + lualine + bufferline
- 编辑增强: mini.ai + mini.surround + grug-far + flash + ufo + trouble v3
- 删除废弃文件: cmp/coding/null-ls/mason/lspconfig/go/python 等旧文件
- 修复: Neovim 0.12 treesitter query 校验报错（noice routes 过滤）
- 新增: NVIM_GUIDE.md 快捷键使用手册

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

nvim/lua/plugins/formatting.lua

@@ -0,0 +1,78 @@
+-- formatting.lua - 代码格式化（conform.nvim）
+
+return {
+  {
+    "stevearc/conform.nvim",
+    event = { "BufReadPre", "BufNewFile" },
+    cmd = { "ConformInfo" },
+    keys = {
+      {
+        "<leader>cf",
+        function()
+          require("conform").format({ async = true, lsp_format = "fallback" })
+        end,
+        mode = { "n", "v" },
+        desc = "格式化代码",
+      },
+      {
+        "<leader>uf",
+        function()
+          vim.b.disable_autoformat = not vim.b.disable_autoformat
+          vim.notify(
+            "当前缓冲区自动格式化 " .. (vim.b.disable_autoformat and "已禁用" or "已启用"),
+            vim.log.levels.INFO
+          )
+        end,
+        desc = "切换当前缓冲区自动格式化",
+      },
+      {
+        "<leader>uF",
+        function()
+          vim.g.disable_autoformat = not vim.g.disable_autoformat
+          vim.notify(
+            "全局自动格式化 " .. (vim.g.disable_autoformat and "已禁用" or "已启用"),
+            vim.log.levels.INFO
+          )
+        end,
+        desc = "切换全局自动格式化",
+      },
+    },
+    opts = {
+      formatters_by_ft = {
+        lua = { "stylua" },
+        go = { "goimports", "gofumpt" },
+        rust = { "rustfmt" },
+        python = { "isort", "ruff_format" },
+        javascript = { "prettierd", "prettier", stop_after_first = true },
+        typescript = { "prettierd", "prettier", stop_after_first = true },
+        javascriptreact = { "prettierd", "prettier", stop_after_first = true },
+        typescriptreact = { "prettierd", "prettier", stop_after_first = true },
+        json = { "prettierd" },
+        jsonc = { "prettierd" },
+        html = { "prettierd" },
+        css = { "prettierd" },
+        scss = { "prettierd" },
+        yaml = { "prettierd" },
+        markdown = { "prettierd" },
+        sh = { "shfmt" },
+        bash = { "shfmt" },
+      },
+
+      formatters = {
+        stylua = {
+          args = { "--indent-type", "Spaces", "--indent-width", "2", "-" },
+        },
+        shfmt = {
+          args = { "-i", "2", "-" },
+        },
+      },
+
+      format_on_save = function(bufnr)
+        if vim.b[bufnr].disable_autoformat or vim.g.disable_autoformat then
+          return
+        end
+        return { timeout_ms = 3000, lsp_format = "fallback" }
+      end,
+    },
+  },
+}