Suppress status messages on stderr when using -o json/yaml

[davixcky]

Summary

• Suppress "Tagged plan..." message on stderr in plan compile, plan create, and plan recompile when -o json or -o yaml is used
• Suppress "Created execution..." message and spinner on stderr in plan run when -o json or -o yaml is used
• Messages still appear in default (human-readable) output mode

These messages go to stderr (not stdout), so they don't technically break JSON parsing when stdout is piped directly. However, they do break common patterns like command 2>&1 | jq . and add noise when structured output is requested.

Reproduce (before)

$ signadot plan compile -f prompt.txt --tag my-tag -o json 2>&1 | head -5
Tagged plan yhqr1xcswwc2j as "stderr-test-before"
{
  "id": "yhqr1xcswwc2j",
  "spec": {
    "params": [

Reproduce (after)

$ signadot plan compile -f prompt.txt --tag my-tag -o json 2>&1 | head -5
{
  "id": "r2fjrvf59lmd4",
  "spec": {
    "params": [
      {

Test plan

• plan compile --tag X -o json 2>&1 produces clean JSON (no "Tagged plan..." line)
• plan compile --tag X (default mode) still shows "Tagged plan..." on stderr
• Same fix applied to plan create and plan recompile
• plan run -o json suppresses "Created execution..." and spinner on stderr
• plan run (default mode) still shows spinner and status messages

🤖 Generated with Claude Code

[scott-cotton]

LGTM

(Please be sure that any actual error messages still do go to stderr)

[davixcky]

@scott-cotton Introduced Root.StatusMsg(w, msg, args...) helper on the config so all subcommands can call cfg.StatusMsg(log, ...) instead of inline if cfg.OutputFormat == ... guards.

Tested across all plan subcommands (compile, create, run, delete) with -o json, -o yaml, and default:

• Status messages (e.g. "Tagged plan...", "Created execution...", spinner) are suppressed in json/yaml mode
• Errors (404s, validation, API failures) always go to stderr regardless of format
• stdout contains only structured output in json/yaml mode (validated JSON parsing)