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/plugins/lsp.lua

@@ -0,0 +1,79 @@
+return {
+  -- Mason: installs LSP servers, formatters, DAP adapters
+  {
+    "williamboman/mason.nvim",
+    cmd = "Mason",
+    build = ":MasonUpdate",
+    opts = {
+      ui = { icons = { package_installed = "✓", package_pending = "➜", package_uninstalled = "✗" } },
+    },
+  },
+
+  -- mason-lspconfig bridges mason ↔ vim.lsp.enable
+  {
+    "williamboman/mason-lspconfig.nvim",
+    dependencies = { "williamboman/mason.nvim" },
+    opts = {
+      ensure_installed = {
+        "lua_ls", "rust_analyzer", "ts_ls", "svelte",
+        "html", "texlab", "marksman", "yamlls", "taplo",
+        -- ltex managed via mason-tool-installer for version control
+      },
+      automatic_installation = false,
+    },
+  },
+
+  -- mason-tool-installer: formatters, linters, DAP, extra servers
+  {
+    "WhoIsSethDaniel/mason-tool-installer.nvim",
+    dependencies = { "williamboman/mason.nvim" },
+    opts = {
+      ensure_installed = {
+        -- LSP servers
+        "lua-language-server",
+        "rust-analyzer",
+        "typescript-language-server",
+        "svelte-language-server",
+        "html-lsp",
+        "texlab",
+        "marksman",
+        "yaml-language-server",
+        "taplo",
+        "ltex-ls",
+        -- Formatters
+        "stylua",
+        "prettier",
+        "rustfmt",
+        "google-java-format",
+        "djlint",
+        -- DAP
+        "codelldb",
+        "js-debug-adapter",
+      },
+      auto_update = false,
+      run_on_start = true,
+    },
+    config = function(_, opts)
+      require("mason-tool-installer").setup(opts)
+      -- Enable servers after mason installs them
+      -- Server configs loaded by init.lua (lua/lsp/*.lua)
+      vim.api.nvim_create_autocmd("User", {
+        pattern = "MasonToolsStartingInstall",
+        once = true,
+        callback = function()
+          vim.schedule(function()
+            vim.lsp.enable({
+              "lua_ls", "rust_analyzer", "ts_ls", "svelte",
+              "html", "texlab", "marksman", "yamlls", "taplo", "ltex",
+            })
+          end)
+        end,
+      })
+      -- Also enable on startup (for machines where tools are already installed)
+      vim.lsp.enable({
+        "lua_ls", "rust_analyzer", "ts_ls", "svelte",
+        "html", "texlab", "marksman", "yamlls", "taplo", "ltex",
+      })
+    end,
+  },
+}