fix(audit): Batch 7-9 dead_code 标注 + TODO 清理 + 文档同步

Batch 7: dead_code 标注统一 (16 处)
- crates/ 9 处: growth, kernel, pipeline, runtime, saas, skills
- src-tauri/ 7 处: classroom, intelligence, browser, mcp
- 统一格式: #[allow(dead_code)] // @reserved: <原因>

Batch 7+: EvolutionEngine L2/L3 10 个未使用 pub 函数
- 全部标注 @reserved: EvolutionEngine L2/L3, post-release integration

Batch 9: TODO → FUTURE 标记 (4 处)
- html.rs: template-based export
- nl_schedule.rs: LLM-assisted parsing
- knowledge/handlers.rs: category_id from upload
- personality_detector.rs: VikingStorage persistence

Batch 5+: Cargo.lock 更新 (serde_yaml_bw 迁移)

全量测试通过: 719 passed, 0 failed

desktop/src-tauri/src/intelligence/extraction_adapter.rs

@@ -313,7 +313,7 @@ pub fn configure_extraction_driver(driver: Arc<dyn LlmDriver>, model: String) {
 }
 
 /// Check if the extraction driver is available (legacy OnceCell path).
-#[allow(dead_code)]
+#[allow(dead_code)] // @reserved: diagnostic check for legacy OnceCell extraction driver
 pub fn is_extraction_driver_configured() -> bool {
     EXTRACTION_DRIVER.get().is_some()
 }
@@ -321,7 +321,7 @@ pub fn is_extraction_driver_configured() -> bool {
 /// Get the global extraction driver (legacy OnceCell path).
 ///
 /// Prefer accessing via `kernel.extraction_driver()` when the Kernel is available.
-#[allow(dead_code)]
+#[allow(dead_code)] // @reserved: legacy accessor, prefer kernel.extraction_driver()
 pub fn get_extraction_driver() -> Option<Arc<TauriExtractionDriver>> {
     EXTRACTION_DRIVER.get().cloned()
 }