Add gofumpt formatting target to Magefile

Add 'mage fmt' target that runs gofumpt -w on the project.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/Magefile.go b/Magefile.go
index 4d79079..2850150 100644
--- a/Magefile.go
+++ b/Magefile.go
@@ -248,6 +248,11 @@ func Coverage() error {
 	return nil
 }
 
+// Fmt formats all Go source files using gofumpt.
+func Fmt() error {
+	return sh.RunV("gofumpt", "-w", ".")
+}
+
 // Vet runs go vet.
 func Vet() error {
 	return sh.RunV("go", "vet", "./...")