chore(fmt): repo-wide gofmt -w sweep — close drift surfaced by ci-pipeline-cleanup Phase 4

Mechanical reformat. The new 'gofmt drift' CI step (added in
ci-pipeline-cleanup Phase 4, commit 0f205a8) surfaced 111 files
with accumulated gofmt drift across cmd/, internal/, and deploy/test/.

Each file's diff is gofmt-standard: whitespace adjustments, intra-
group import sorting (alphabetical by import path within blank-line-
separated groups), and struct-tag column alignment. No semantic
changes — verified via 'git diff --ignore-all-space' which shows only
the line-position deltas from import reordering.

The gate stays in place after this commit. Going forward it catches
gofmt drift at PR time.

internal/service/agent_test.go

@@ -10,7 +10,6 @@ import (
 	"github.com/shankar0123/certctl/internal/domain"
 )
 
-
 func TestRegisterAgent(t *testing.T) {
 	ctx := context.Background()
 	agentRepo := &mockAgentRepo{