nvim,tmux,kitty: full config overhaul (AstroNvim → native 0.12)

Replaces AstroNvim v5 with from-scratch Neovim 0.12 config using
vim.lsp.config()/vim.lsp.enable() natively, lazy.nvim, blink.cmp,
and smart-splits tmux integration.

tmux: new C-Space prefix, hjkl pane nav, resize key table, tpm plugins.
kitty: add allow_remote_control for smart-splits.

dot_config/nvim/lua/keymaps.lua

@@ -0,0 +1,43 @@
+local map = vim.keymap.set
+
+-- Better window navigation
+map("n", "<leader>|", "<C-w>v", { desc = "Vertical split" })
+map("n", "<leader>-", "<C-w>s", { desc = "Horizontal split" })
+map("n", "<leader>w", "<C-w>q", { desc = "Close split" })
+
+-- Buffer navigation
+map("n", "]b", "<cmd>bnext<cr>", { desc = "Next buffer" })
+map("n", "[b", "<cmd>bprevious<cr>", { desc = "Prev buffer" })
+map("n", "<leader>bd", "<cmd>bdelete<cr>", { desc = "Delete buffer" })
+map("n", "<leader>bo", "<cmd>%bd|e#|bd#<cr>", { desc = "Close other buffers" })
+
+-- Diagnostics
+map("n", "]d", vim.diagnostic.goto_next, { desc = "Next diagnostic" })
+map("n", "[d", vim.diagnostic.goto_prev, { desc = "Prev diagnostic" })
+
+-- Move lines
+map("v", "J", ":m '>+1<CR>gv=gv", { desc = "Move selection down" })
+map("v", "K", ":m '<-2<CR>gv=gv", { desc = "Move selection up" })
+
+-- Keep cursor centered
+map("n", "<C-d>", "<C-d>zz")
+map("n", "<C-u>", "<C-u>zz")
+map("n", "n", "nzzzv")
+map("n", "N", "Nzzzv")
+
+-- Clear search highlight
+map("n", "<Esc>", "<cmd>nohlsearch<cr>")
+
+-- Don't yank on paste in visual mode
+map("x", "<leader>p", '"_dP', { desc = "Paste without yanking" })
+
+-- Better indenting
+map("v", "<", "<gv")
+map("v", ">", ">gv")
+
+-- Save
+map({ "n", "i" }, "<C-s>", "<cmd>w<cr>", { desc = "Save" })
+
+-- Quit
+map("n", "<leader>q", "<cmd>q<cr>", { desc = "Quit" })
+map("n", "<leader>Q", "<cmd>qa<cr>", { desc = "Quit all" })