Rewrite nvim-treesitter config for new main-branch API

The nvim-treesitter rewrite removed nvim-treesitter.configs entirely.
Now uses require('nvim-treesitter').install() and a FileType autocmd
for dynamic attach, mirroring current kickstart.nvim.

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

shared/.config/nvim/init.lua

@@ -257,17 +257,36 @@ require('lazy').setup({
   --------------------------------------------------------------------------
   {
     'nvim-treesitter/nvim-treesitter',
-    build = ':TSUpdate',
+    lazy   = false,
+    build  = ':TSUpdate',
+    branch = 'main',
     config = function()
-      require('nvim-treesitter.configs').setup({
+      local parsers = { 'bash', 'json', 'lua', 'luadoc', 'markdown', 'markdown_inline', 'vim', 'vimdoc', 'yaml' }
-        ensure_installed = (function()
+      vim.list_extend(parsers, _lang.parsers or {})
-          local t = { 'bash', 'json', 'lua', 'luadoc', 'markdown', 'markdown_inline', 'vim', 'vimdoc', 'yaml' }
+      require('nvim-treesitter').install(parsers)
-          vim.list_extend(t, _lang.parsers or {})
+
-          return t
+      local function try_attach(buf, lang)
-        end)(),
+        if not vim.treesitter.language.add(lang) then return end
-        auto_install = true,
+        vim.treesitter.start(buf, lang)
-        highlight    = { enable = true },
+        if vim.treesitter.query.get(lang, 'indents') then
-        indent       = { enable = true },
+          vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"
+        end
+      end
+
+      local available = require('nvim-treesitter').get_available()
+      vim.api.nvim_create_autocmd('FileType', {
+        callback = function(args)
+          local lang = vim.treesitter.language.get_lang(args.match)
+          if not lang then return end
+          local installed = require('nvim-treesitter').get_installed 'parsers'
+          if vim.tbl_contains(installed, lang) then
+            try_attach(args.buf, lang)
+          elseif vim.tbl_contains(available, lang) then
+            require('nvim-treesitter').install(lang):await(function() try_attach(args.buf, lang) end)
+          else
+            try_attach(args.buf, lang)
+          end
+        end,
       })
     end,
   },