style: gofmt

Formatting only (struct field alignment, import ordering) across the
files that didn't comply — no semantic changes.

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

pkg/llm/types_test.go

@@ -139,7 +139,5 @@ func TestStreamChunk_JSON(t *testing.T) {
 	}
 }
 
-
-
 func float32Ptr(f float32) *float32 { return &f }
 func intPtr(i int) *int             { return &i }