feat(growth): L2 技能进化核心 — PatternAggregator+SkillGenerator+QualityGate+EvolutionEngine

- PatternAggregator: 经验模式聚合，找出 reuse_count>=threshold 的可固化模式
- SkillGenerator: LLM prompt 构建 + JSON 解析 + 自动提取 JSON 块
- QualityGate: 置信度/冲突/格式质量门控
- EvolutionEngine: 中枢调度器，协调 L2 触发检查+技能生成+质量验证

新增 24 个测试（87→111），全 workspace 0 error。

crates/zclaw-growth/src/lib.rs

@@ -67,6 +67,10 @@ pub mod summarizer;
 pub mod experience_store;
 pub mod experience_extractor;
 pub mod profile_updater;
+pub mod pattern_aggregator;
+pub mod skill_generator;
+pub mod quality_gate;
+pub mod evolution_engine;
 
 // Re-export main types for convenience
 pub use types::{
@@ -101,6 +105,10 @@ pub use retrieval::{EmbeddingClient, MemoryCache, QueryAnalyzer, SemanticScorer}
 pub use summarizer::SummaryLlmDriver;
 pub use experience_extractor::ExperienceExtractor;
 pub use profile_updater::UserProfileUpdater;
+pub use pattern_aggregator::{AggregatedPattern, PatternAggregator};
+pub use skill_generator::{SkillCandidate, SkillGenerator};
+pub use quality_gate::{QualityGate, QualityReport};
+pub use evolution_engine::{EvolutionConfig, EvolutionEngine};
 
 /// Growth system configuration
 #[derive(Debug, Clone)]