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/lsp/rust_analyzer.lua

@@ -0,0 +1,40 @@
+vim.lsp.config("rust_analyzer", {
+  settings = {
+    ["rust-analyzer"] = {
+      cargo = {
+        allFeatures = true,
+        loadOutDirsFromCheck = true,
+        runBuildScripts = true,
+      },
+      checkOnSave = {
+        allFeatures = true,
+        command = "clippy",
+        extraArgs = { "--no-deps" },
+      },
+      procMacro = {
+        enable = true,
+        ignored = {
+          ["async-trait"] = { "async_trait" },
+          ["napi-derive"] = { "napi" },
+          ["async-recursion"] = { "async_recursion" },
+        },
+      },
+      inlayHints = {
+        bindingModeHints = { enable = false },
+        closingBraceHints = { minLines = 25 },
+        lifetimeElisionHints = { enable = "never" },
+        typeHints = { enable = true },
+      },
+    },
+  },
+})
+
+-- Support project-local override (e.g. Tauri: root_dir = src-tauri/)
+local local_cfg_path = vim.fn.getcwd() .. "/.nvim.lua"
+local local_cfg = vim.secure.read(local_cfg_path)
+if local_cfg then
+  local ok, err = pcall(loadstring(local_cfg))
+  if not ok then
+    vim.notify("rust_analyzer local config error: " .. tostring(err), vim.log.levels.WARN)
+  end
+end