Update nvim config: split plugins, update README

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

nvim/lua/plugins/claudecode.lua

@@ -0,0 +1,26 @@
+return {
+  {
+    "coder/claudecode.nvim",
+    dependencies = { "folke/snacks.nvim" },
+    config = true,
+    keys = {
+      { "<leader>a", nil, desc = "AI/Claude Code" },
+      { "<leader>ac", "<cmd>ClaudeCode<cr>", desc = "Toggle Claude" },
+      { "<leader>af", "<cmd>ClaudeCodeFocus<cr>", desc = "Focus Claude" },
+      { "<leader>ar", "<cmd>ClaudeCode --resume<cr>", desc = "Resume Claude" },
+      { "<leader>aC", "<cmd>ClaudeCode --continue<cr>", desc = "Continue Claude" },
+      { "<leader>am", "<cmd>ClaudeCodeSelectModel<cr>", desc = "Select Claude model" },
+      { "<leader>ab", "<cmd>ClaudeCodeAdd %<cr>", desc = "Add current buffer" },
+      { "<leader>as", "<cmd>ClaudeCodeSend<cr>", mode = "v", desc = "Send to Claude" },
+      {
+        "<leader>as",
+        "<cmd>ClaudeCodeTreeAdd<cr>",
+        desc = "Add file",
+        ft = { "NvimTree", "neo-tree", "oil", "minifiles", "netrw" },
+      },
+      -- Diff management
+      { "<leader>aa", "<cmd>ClaudeCodeDiffAccept<cr>", desc = "Accept diff" },
+      { "<leader>ad", "<cmd>ClaudeCodeDiffDeny<cr>", desc = "Deny diff" },
+    },
+  },
+}