Refactor Hermes opportunity analyzer into modules

[SecretSettler]

Summary

• Split the large Hermes opportunity analyzer script into the contextpilot.hermes_opportunities package
• Keep scripts/analyze_hermes_context_opportunities.py as a stable thin wrapper
• Preserve privacy guardrails and keep opportunity sections advisory/shadow-only
• Improve markdown wording so processed-payload chars are reported separately from derived chars/4 counters

Verification

• python3 -m pytest tests/test_hermes_context_opportunity_analyzer.py tests/test_contextpilot_savings.py tests/test_contextpilot_savings_skill.py tests/test_hermes_contextpilot_monitor.py -q
• python3 -m pytest -q
• python3 scripts/analyze_hermes_context_opportunities.py --since-hours 24 --out-dir /tmp/contextpilot_modular_check2 --date modular_check2 --top-n 3
• Claude Code read-only review: SHIP, no blockers