fix(growth): 二次审计修复 — 6项 CRITICAL/HIGH/MEDIUM 全部修复

CRITICAL-1/2: json_utils 花括号匹配改为括号平衡算法
  - 处理字符串字面量中的花括号和转义引号
  - 新增 5 个测试（平衡匹配、字符串内花括号、转义引号、extract_string_array）

HIGH-4: EvolutionMiddleware 只取第一个事件(remove(0))，不丢弃后续
HIGH-5: EvolutionMiddleware 先 read() 判空再 write()，减少锁竞争
HIGH-7: from_experience_store 使用传入 store 的 viking 实例（不再忽略参数）
  - ExperienceStore 新增 viking() getter

MEDIUM-9: skill_generator + workflow_composer JSON 数组解析去重
  - 新增 json_utils::extract_string_array() 共享函数
MEDIUM-14: EvolutionMiddleware 注入文本去除多余缩进空格

测试: zclaw-growth 133 tests, zclaw-runtime 87 tests, workspace 0 failures

crates/zclaw-growth/src/lib.rs

@@ -107,7 +107,7 @@ pub use experience_store::{Experience, ExperienceStore};
 pub use retrieval::{EmbeddingClient, MemoryCache, QueryAnalyzer, SemanticScorer};
 pub use summarizer::SummaryLlmDriver;
 pub use experience_extractor::ExperienceExtractor;
-pub use json_utils::extract_json_block;
+pub use json_utils::{extract_json_block, extract_string_array};
 pub use profile_updater::{ProfileFieldUpdate, UserProfileUpdater};
 pub use pattern_aggregator::{AggregatedPattern, PatternAggregator};
 pub use skill_generator::{SkillCandidate, SkillGenerator};