refactor(conform): format on demand, not on save

Agents run stylua/biome/rustfmt themselves, and a save-time reformat
races their in-flight writes to the same buffer. Timeout and LSP
fallback move to default_format_opts so <leader>fm (NvChad's binding)
keeps the same behaviour; conform now lazy-loads on first use.

Drops the /contrib/ skip — explicit invocation is already the opt-in.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lua/configs/conform.lua

@@ -20,17 +20,12 @@ local options = {
     },
   },
 
-  format_after_save = function()
-    local buf_path = vim.api.nvim_buf_get_name(0)
-    if buf_path:find "/contrib/" then
-      return nil
-    end
-
-    return {
-      timeout_ms = 1000,
-      lsp_format = "fallback",
-    }
-  end,
+  -- No format-on-save: agents run these formatters themselves, and a save-time
+  -- reformat races their in-flight writes. Format on demand with <leader>fm.
+  default_format_opts = {
+    timeout_ms = 1000,
+    lsp_format = "fallback",
+  },
 }
 
 return options

lua/plugins/init.lua

@@ -1,7 +1,7 @@
 return {
   {
     "stevearc/conform.nvim",
-    event = "BufWritePre",
+    cmd = "ConformInfo",
     opts = require "configs.conform",
   },
 }