Add nil guard to lazy.load and custom mini.diff mappings

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lua/lazy.lua

@@ -7,7 +7,9 @@ M.load = function(name, fn)
         return
     end
     M._loaded[name] = true
+    if fn then
         fn()
+    end
 end
 
 M.on_event = function(name, event, pattern, fn)

lua/pack.lua

@@ -128,6 +128,10 @@ end)
 lazy.on_event("diff", "BufReadPost", "*", function()
 	require("mini.diff").setup({
 		source = require("mini.diff").gen_source.git({ index = false }),
+		mappings = {
+			apply = "gs",
+			textobject = "",
+		},
 	})
 end)