fix(tauri): replace silent let _ = with structured logging across 20 modules

Replace error-swallowing let _ = patterns with tracing::warn! in browser,
classroom, gateway, intelligence, memory, pipeline, secure_storage, and
viking command handlers. Ensures errors are observable in production logs.

desktop/src-tauri/src/pipeline_commands/presentation.rs

@@ -9,6 +9,7 @@ use super::types::PipelineInputInfo;
 use super::PipelineState;
 
 /// Analyze presentation data
+// @connected
 #[tauri::command]
 pub async fn analyze_presentation(
     data: Value,
@@ -43,6 +44,7 @@ pub struct PipelineTemplateInfo {
 /// Templates are pipeline YAML files that users can browse and instantiate.
 /// They live in `pipelines/_templates/` and are not directly runnable
 /// (they serve as blueprints).
+// @reserved: 暂无前端集成
 #[tauri::command]
 pub async fn pipeline_templates(
     state: State<'_, Arc<PipelineState>>,