[4.11] rescue-from-main workflow helper 추가

[devRonPark]

Summary

• Add Codex repo-scoped skill -from-main for moving accidental main/master work to a content-named branch, then commit, push, and draft PR.
• Add Claude Code custom command /rescue-from-main with matching safety checks.
• Register the helper in AGENTS.md, README.md, BLUEPRINT.md, task planning records, and harness state docs.

Verification

• PASS: test -f .agents/skills/rescue-from-main/SKILL.md && test -f .claude/commands/rescue-from-main.md && grep -q 'rescue-from-main' AGENTS.md && grep -q 'rescue-from-main' README.md && grep -q 'rescue-from-main' BLUEPRINT.md
• PASS: python3 scripts/validate_tasks.py
• PASS: python3 scripts/sync_plans.py --check
• PASS: all .agents/skills/*/SKILL.md files have name and description frontmatter
• PASS: python3 -m unittest tests.test_tasks tests.test_planning -v (18 tests)

Acceptance Evidence

Task 4.11 acceptance command passed after switching to task/4.11-rescue-from-main-helper.

Residual Risk

• This is a procedural helper; live behavior still depends on GitHub CLI auth, remote permissions, and branch protection settings in the target repository.