HOK-1392: Suppress noisy ready stderr logs

[timogilvie]

Summary

• Removed printMergeConflictStatus from tools/ready.ts which was writing merge conflict warnings to stderr (e.g. ⚠️ MERGE CONFLICT: PR #241 has conflicts with main), causing them to appear as ERROR-level log entries
• Added 2>/dev/null to gh pr checks shell commands in ready-stage.ts to suppress GitHub CLI warnings (e.g. no checks reported on the '...' branch) that were leaking into logs as errors
• Updated tests/launch-ready-phase.test.sh to reflect that success-path stderr is no longer logged
• Added unit tests in ready-stage.test.ts to verify stderr suppression on gh pr checks calls

Changes

• shared/lib/ready-stage.ts — Added 2>/dev/null to two gh pr checks invocations
• tools/ready.ts — Removed printMergeConflictStatus function and its call site
• shared/lib/ready-stage.test.ts — Added tests verifying stderr is suppressed in checkCIStatus and gatherPRContext
• tests/launch-ready-phase.test.sh — Updated assertions for success-path stderr behavior
• tests/lifecycle-harness.test.sh / tests/lifecycle-scenarios.test.sh — Added missing _restore_inflight_task_window_if_missing stubs

Test plan

• Existing test suite covers the changed paths
• New unit tests in ready-stage.test.ts explicitly verify 2>/dev/null is present on gh pr checks commands
• Shell test assertions updated to confirm success-path ready stderr is no longer logged as an error

Self-review

• Review tool: review-changes.ts main --json --operating-mode normal
• Verdict: ready (exit code 0, 0 findings)
• Iterations: 1

Closes HOK-1392