Add markdown linting commands and update keymaps

- Introduced commands to enable/disable automatic markdown linting.
- Updated keymaps to reflect changes in markdown linting behavior.

lua/plugins/nvim-lint.lua

@@ -13,7 +13,7 @@ return {
       javascriptreact = { "eslint_d" },
       typescript = { "eslint_d" },
       typescriptreact = { "eslint_d" },
-      markdown = { "markdownlint" },
+      -- markdown linting: manual only (see keymap below)
       php = { "phpcs" },
       -- Python: ruff LSP handles linting
     }
@@ -78,5 +78,24 @@ return {
         lint.try_lint()
       end,
     })
+
+    -- Commands to enable/disable automatic markdown linting
+    vim.api.nvim_create_user_command("LintMarkdownEnable", function()
+      lint.linters_by_ft.markdown = { "markdownlint" }
+      vim.notify("Markdown linting enabled (automatic)", vim.log.levels.INFO)
+      -- Lint immediately
+      if vim.bo.filetype == "markdown" then
+        lint.try_lint()
+      end
+    end, { desc = "Enable automatic markdown linting" })
+
+    vim.api.nvim_create_user_command("LintMarkdownDisable", function()
+      lint.linters_by_ft.markdown = nil
+      vim.notify("Markdown linting disabled", vim.log.levels.INFO)
+      -- Clear existing diagnostics for markdown buffers
+      if vim.bo.filetype == "markdown" then
+        vim.diagnostic.reset(lint.get_namespace("markdownlint"))
+      end
+    end, { desc = "Disable automatic markdown linting" })
   end,
 }