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/git.lua

@@ -0,0 +1,63 @@
+return {
+  -- Gutter signs, hunk navigation, inline blame
+  {
+    "lewis6991/gitsigns.nvim",
+    event = { "BufReadPost", "BufNewFile" },
+    opts = {
+      signs = {
+        add          = { text = "▎" },
+        change       = { text = "▎" },
+        delete       = { text = "" },
+        topdelete    = { text = "" },
+        changedelete = { text = "▎" },
+        untracked    = { text = "▎" },
+      },
+      on_attach = function(bufnr)
+        local gs = package.loaded.gitsigns
+        local map = function(mode, lhs, rhs, desc)
+          vim.keymap.set(mode, lhs, rhs, { buffer = bufnr, desc = desc })
+        end
+
+        -- Navigation
+        map("n", "]h", function()
+          if vim.wo.diff then return "]h" end
+          vim.schedule(function() gs.next_hunk() end)
+          return "<Ignore>"
+        end, "Next hunk")
+        map("n", "[h", function()
+          if vim.wo.diff then return "[h" end
+          vim.schedule(function() gs.prev_hunk() end)
+          return "<Ignore>"
+        end, "Prev hunk")
+
+        -- Actions
+        map("n", "<leader>hs", gs.stage_hunk, "Stage hunk")
+        map("n", "<leader>gu", gs.undo_stage_hunk, "Undo stage hunk")
+        map("n", "<leader>gh", gs.preview_hunk, "Preview hunk")
+        map("n", "<leader>hb", gs.toggle_current_line_blame, "Toggle blame")
+        map("n", "<leader>gb", gs.toggle_current_line_blame, "Toggle blame")
+        map("n", "<leader>gd", gs.diffthis, "Diff this")
+      end,
+    },
+  },
+
+  -- Magit-style full git interface
+  {
+    "NeogitOrg/neogit",
+    dependencies = {
+      "nvim-lua/plenary.nvim",
+      "sindrets/diffview.nvim",
+      "nvim-telescope/telescope.nvim",
+    },
+    cmd = "Neogit",
+    keys = {
+      { "<leader>gg", "<cmd>Neogit<cr>", desc = "Neogit" },
+    },
+    opts = {
+      integrations = {
+        telescope = true,
+        diffview = true,
+      },
+    },
+  },
+}