fix(growth): 穷尽审计修复 — tracker timeline 断链 + 文档更新

P1-1: tracker.rs record_learning 改为通过 MemoryEntry 存储
      (之前用 store_metadata 存但 get_timeline 用 find_by_prefix 读，
       两条路径不交叉，timeline 永远返回空)

P2-4: extractor.rs 移除未使用的 _llm_driver 绑定，改为 is_none() 检查

P2-5: lib.rs 模块文档更新，反映实际 17 个模块而非原始 4 个

profile_updater.rs: 添加注释说明只收集 update_field 支持的字段

测试: zclaw-growth 137 tests, zclaw-runtime 87 tests, 0 failures

crates/zclaw-growth/src/lib.rs

@@ -5,10 +5,13 @@
 //!
 //! # Architecture
 //!
-//! The growth system consists of four main components:
+//! The growth system consists of several subsystems:
+//!
+//! ## Memory Pipeline (L0-L2)
 //!
 //! 1. **MemoryExtractor** (`extractor`) - Analyzes conversations and extracts
-//!    preferences, knowledge, and experience using LLM.
+//!    preferences, knowledge, and experience using LLM. Supports combined extraction
+//!    (single LLM call for memories + experiences + profile signals).
 //!
 //! 2. **MemoryRetriever** (`retriever`) - Performs semantic search over
 //!    stored memories to find contextually relevant information.
@@ -19,6 +22,28 @@
 //! 4. **GrowthTracker** (`tracker`) - Tracks growth metrics and evolution
 //!    over time.
 //!
+//! ## Evolution Engine (L1-L3)
+//!
+//! 5. **ExperienceStore** (`experience_store`) - FTS5-backed structured experience storage.
+//!
+//! 6. **PatternAggregator** (`pattern_aggregator`) - Collects high-frequency patterns for L2.
+//!
+//! 7. **SkillGenerator** (`skill_generator`) - LLM-driven SKILL.md content generation.
+//!
+//! 8. **QualityGate** (`quality_gate`) - Validates candidate skills (confidence, conflicts).
+//!
+//! 9. **EvolutionEngine** (`evolution_engine`) - Orchestrates L1/L2/L3 evolution phases.
+//!
+//! 10. **WorkflowComposer** (`workflow_composer`) - Extracts tool chain patterns for Pipeline YAML.
+//!
+//! 11. **FeedbackCollector** (`feedback_collector`) - Trust score management with decay.
+//!
+//! ## Support Modules
+//!
+//! 12. **VikingAdapter** (`viking_adapter`) - Storage abstraction (in-memory + SQLite backends).
+//! 13. **Summarizer** (`summarizer`) - L0/L1 summary generation.
+//! 14. **JsonUtils** (`json_utils`) - Shared JSON parsing utilities.
+//!
 //! # Storage
 //!
 //! All memories are stored in OpenViking with a URI structure: