[log] Add debug logging to utility and workflow files

[github-actions]

Summary

Adds namespaced debug loggers and meaningful log calls to five previously unlogged files following the project's logging guidelines in AGENTS.md. Each file declares a package-level logger via logger.New("pkg:filename") and emits 2-4 log calls at function entry, branch decisions, and error paths.

Files modified

• pkg/jsonutil/json.go — logger jsonutil:json; logs encode failures and marshalled byte count
• pkg/errorutil/errors.go — logger errorutil:errors; logs when an error is classified as 404/403/410
• pkg/syncutil/onceloader.go — logger syncutil:onceloader; logs cache miss/hit, loader outcome, reset, and override events
• pkg/workflow/workflow_inputs_extractor.go — logger workflow:workflow_inputs_extractor; logs YAML/markdown read paths, frontmatter extraction failures, and resolved input counts per trigger
• pkg/workflow/safe_outputs_workflow_helpers.go — logger workflow:safe_outputs_workflow_helpers; logs tool generation context, required-input counts, and workflow extension resolution branches

Constraints honored

• Maximum 5 files modified, no test files touched
• All log arguments are side-effect-free (plain identifiers, lengths, error values)
• Namespaces follow the pkg:filename convention from AGENTS.md

Test plan

• make build succeeds with no compilation errors
• make test-unit (not run in this environment due to sandbox restrictions; package-level builds are green)
• Verify debug output by running DEBUG=workflow:workflow_inputs_extractor,jsonutil:*,errorutil:*,syncutil:*,workflow:safe_outputs_workflow_helpers ./gh-aw compile <workflow> and confirming the new log lines appear

🤖 Generated with [Claude Code]((claude.com/redacted)

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• expires on May 25, 2026, 4:39 AM UTC