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/blink.lua

@@ -0,0 +1,99 @@
+-- blink.lua - blink.cmp 补全引擎（替换 nvim-cmp）
+
+return {
+  {
+    "saghen/blink.cmp",
+    version = "*",
+    event = "InsertEnter",
+    dependencies = {
+      "rafamadriz/friendly-snippets",
+      { "L3MON4D3/LuaSnip", version = "v2.*" },
+    },
+    opts = {
+      keymap = {
+        preset = "default",
+        ["<C-Space>"] = { "show", "show_documentation", "hide_documentation" },
+        ["<C-e>"] = { "hide" },
+        ["<CR>"] = { "accept", "fallback" },
+        ["<Tab>"] = { "snippet_forward", "fallback" },
+        ["<S-Tab>"] = { "snippet_backward", "fallback" },
+        ["<C-n>"] = { "select_next", "fallback" },
+        ["<C-p>"] = { "select_prev", "fallback" },
+        ["<C-b>"] = { "scroll_documentation_up", "fallback" },
+        ["<C-f>"] = { "scroll_documentation_down", "fallback" },
+      },
+
+      appearance = {
+        nerd_font_variant = "mono",
+      },
+
+      snippets = {
+        expand = function(snippet)
+          require("luasnip").lsp_expand(snippet)
+        end,
+        active = function(filter)
+          if filter and filter.direction then
+            return require("luasnip").jumpable(filter.direction)
+          end
+          return require("luasnip").in_snippet()
+        end,
+        jump = function(direction)
+          require("luasnip").jump(direction)
+        end,
+      },
+
+      sources = {
+        default = { "lsp", "path", "snippets", "buffer" },
+        providers = {
+          lsp = { score_offset = 100 },
+          path = { score_offset = 50 },
+          snippets = { score_offset = 40 },
+          buffer = { score_offset = 10 },
+        },
+      },
+
+      completion = {
+        accept = { auto_brackets = { enabled = true } },
+        menu = {
+          border = "rounded",
+          draw = {
+            treesitter = { "lsp" },
+            columns = {
+              { "label", "label_description", gap = 1 },
+              { "kind_icon", "kind" },
+            },
+          },
+        },
+        documentation = {
+          auto_show = true,
+          auto_show_delay_ms = 200,
+          window = { border = "rounded" },
+        },
+        ghost_text = { enabled = true },
+      },
+
+      signature = {
+        enabled = true,
+        window = { border = "rounded" },
+      },
+    },
+
+    config = function(_, opts)
+      -- LuaSnip 加载 vscode 风格的代码片段
+      require("luasnip.loaders.from_vscode").lazy_load()
+      require("blink.cmp").setup(opts)
+    end,
+  },
+
+  -- LuaSnip 代码片段引擎
+  {
+    "L3MON4D3/LuaSnip",
+    version = "v2.*",
+    build = "make install_jsregexp",
+    dependencies = { "rafamadriz/friendly-snippets" },
+    opts = {
+      history = true,
+      delete_check_events = "TextChanged",
+    },
+  },
+}