feat: add self-evolution plugin — agent self-optimization system

Add a comprehensive self-evolution system that enables Hermes Agent
to continuously improve through automated analysis and optimization:

Core components:
- reflection_engine: Nightly session analysis (1:00 AM)
- evolution_proposer: Generate improvement proposals from insights
- quality_scorer: Multi-dimensional session quality evaluation
- strategy_injector: Inject learned strategies into new sessions
- strategy_compressor: Strategy optimization and deduplication
- git_analyzer: Code change pattern analysis
- rule_engine: Pattern-based rule generation
- feishu_notifier: Feishu card notifications for evolution events

Storage:
- db.py: SQLite telemetry storage
- strategy_store: Persistent strategy storage
- models.py: Data models

Plugin integration:
- plugin.yaml, hooks.py, __init__.py for plugin system
- cron_jobs.py for scheduled tasks

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

self_evolution/prompts/reflection.md

@@ -0,0 +1,7 @@
+## 概况
+- 时段: {period_range}
+- Session 数: {sessions_count}, 平均质量: {avg_score}
+- 工具调用: {total_invocations} 次, 成功率 {success_rate}%
+
+## 数据
+{data_json}