feat: bootstrap the skills repo with loong-monitor

[chumyin]

Summary

• bootstrap the repository layout for team-maintained skills
• add the first skill, loong-monitor, for evidence-backed monitoring of loongclaw-ai/loongclaw activity
• include a GitHub activity collector, previous-window comparison support, confidence scoring, and a full Markdown report generator
• add one-command rolling and calendar presets for weekly, monthly, and quarterly monitoring runs
• add fixed-directory publishing via --copy-to, including per-run, latest-per-preset, latest, and published index views
• add retry handling for transient GitHub CLI/API timeout failures during collection

Validation

• python3 /Users/chum/.codex/skills/.system/skill-creator/scripts/quick_validate.py /Users/chum/skills/skills/loong-monitor
• python3 -m py_compile skills/loong-monitor/scripts/collect_repo_activity.py skills/loong-monitor/scripts/generate_report.py skills/loong-monitor/scripts/run_monitor_cycle.py
• python3 skills/loong-monitor/scripts/collect_repo_activity.py --repo loongclaw-ai/loongclaw --days 30 --limit 20 --detail-limit 10 --compare-previous --output /tmp/loong-monitor-deep
• python3 skills/loong-monitor/scripts/generate_report.py --activity /tmp/loong-monitor-deep/activity.json --output /tmp/loong-monitor-deep/report.md
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset weekly --repo loongclaw-ai/loongclaw --output-root /tmp/loong-monitor-presets --limit 15 --detail-limit 8
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset calendar-week --repo loongclaw-ai/loongclaw --output-root /tmp/loong-monitor-presets --limit 12 --detail-limit 6
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset calendar-month --repo loongclaw-ai/loongclaw --until 2026-03-31 --output-root /tmp/loong-monitor-presets --limit 12 --detail-limit 6
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset quarter --repo loongclaw-ai/loongclaw --output-root /tmp/loong-monitor-presets --limit 10 --detail-limit 5
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset calendar-quarter --repo loongclaw-ai/loongclaw --until 2026-03-31 --output-root /tmp/loong-monitor-presets --limit 10 --detail-limit 5
• python3 skills/loong-monitor/scripts/run_monitor_cycle.py --preset weekly --repo loongclaw-ai/loongclaw --output-root /tmp/loong-monitor-runs --copy-to /tmp/loong-monitor-published --limit 8 --detail-limit 4

Closes #1