fix(growth): Evolution Engine 审计修复 — 7项全部完成

HIGH-1: 提取共享 json_utils.rs，skill_generator/workflow_composer 去重
HIGH-2: FeedbackCollector Vec→HashMap，消除 unwrap() panic 风险
HIGH-3: ProfileUpdater 改为 collect_updates() 返回字段列表，
        growth.rs 直接 async 调用 update_field()，不再用 no-op 闭包
MEDIUM-1: EvolutionMiddleware 注入后自动 drain，防止重复注入
MEDIUM-2: PatternAggregator tools 提取改为直接收集 context 值
MEDIUM-3: evolution_engine.rs 移除 4 个未使用 imports
MEDIUM-4: workflow_composer parse_response pattern 参数加下划线
MEDIUM-7: SkillCandidate 添加 version 字段（默认=1）

测试: zclaw-growth 128 tests, zclaw-runtime 86 tests, workspace 0 failures

crates/zclaw-growth/src/lib.rs

@@ -65,6 +65,7 @@ pub mod storage;
 pub mod retrieval;
 pub mod summarizer;
 pub mod experience_store;
+pub mod json_utils;
 pub mod experience_extractor;
 pub mod profile_updater;
 pub mod pattern_aggregator;
@@ -106,7 +107,8 @@ pub use experience_store::{Experience, ExperienceStore};
 pub use retrieval::{EmbeddingClient, MemoryCache, QueryAnalyzer, SemanticScorer};
 pub use summarizer::SummaryLlmDriver;
 pub use experience_extractor::ExperienceExtractor;
-pub use profile_updater::UserProfileUpdater;
+pub use json_utils::extract_json_block;
+pub use profile_updater::{ProfileFieldUpdate, UserProfileUpdater};
 pub use pattern_aggregator::{AggregatedPattern, PatternAggregator};
 pub use skill_generator::{SkillCandidate, SkillGenerator};
 pub use quality_gate::{QualityGate, QualityReport};