feat(rag): harden post-LightRAG runtime

Retire legacy OCR/media/evidence fallbacks, add local-folder event bus and Page Aggregate guards, and archive completed design checklists.

Validation: cargo test -p mnote-web -- --test-threads=1; cargo test --workspace -- --test-threads=1; git diff --check; codegraph sync .; codegraph_status.

rust/crates/mnote-web/src/routes/resource_trash.rs

@@ -224,7 +224,7 @@ async fn record_media_empty_trash_artifacts(
     let plan = RuntimeCommandExecutionPlan {
         command_name: command.name.clone(),
         command_id: command.command_id.clone(),
-        function_name: "mediaAssets:emptyTrashByWorkspace".into(),
+        function_name: command.name.clone(),
         workspace_id: Some(workspace_id.to_string()),
         request_id: context.trace.request_id.clone(),
         trace_id: context.trace.trace_id.clone(),