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.

scripts/TESTING_REFERENCE.md

@@ -35,8 +35,8 @@ node scripts/task490-runtime-surfaces-smoke.js
 - 入口与认证：`task114-rust-web-gateway-entry-smoke.js`、`task159-auth-entry-smoke.js`、`task097-homepage-entry-smoke.js`
 - Rust SSR 文档页 / Page Aggregate：local-first 默认优先 `task167-local-markdown-title-body-options-no-convex-smoke.js`；Page Aggregate browser conversion / compat fallback 改动补跑 `task522-page-aggregate-compat-fallback-contract.js`；cloud/control-plane 文档可补跑 `task110-page-title-single-truth-smoke.js`、`task-page-aggregate-body-sync-smoke.js`、`task-page-aggregate-options-sync-smoke.js`、`task-page-aggregate-refresh-persistence-smoke.js`
 - leptos-tiptap runtime surface：`task490-runtime-surfaces-smoke.js`；需要验证保存回读可补跑 `task121-rust-web-editor-island-hydration-smoke.js`，但它仍使用 `/api/tree/commands create` 准备文档，不作为无 Convex 默认基线；需要验证浮层互斥和更多菜单状态时再跑 `task158-e30-menu-state-smoke.js`
-- local-first 本地工作区：`task164-desktop-hot-local-folder-main-entry-smoke.js`、`task166-local-first-managed-workspace-no-convex-smoke.js`、`task167-local-markdown-title-body-options-no-convex-smoke.js`、`task436-local-markdown-open-document-external-change-smoke.js`、`task443-local-markdown-asset-upload-smoke.js`、`task451-local-markdown-conflict-resolution-ui-smoke.js`、`task452-local-search-index-browser-smoke.js`、`task453-local-folder-page-ai-changed-files-smoke.js`；WorkspacePath / ObjectIdentity runtime 消费统一改动补跑 `task524-workspace-object-identity-matrix-smoke.js`
-- LightRAG 资料库：`task534-knowledge-rag-source-management-scope-smoke.js` 覆盖本地文件夹 source 加入资料库、registry 状态与范围管理；`task529-knowledge-rag-citation-resource-tab-smoke.js`、`task530-knowledge-rag-page-ai-final-answer-smoke.js` 覆盖资料库引用回到资源页与 Page AI 最终回答。旧 `task526-local-folder-ocr-api-smoke.js` / OCR sidecar 链路已退役并软归档。
+- local-first 本地工作区：`task164-desktop-hot-local-folder-main-entry-smoke.js`、`task166-local-first-managed-workspace-no-convex-smoke.js`、`task167-local-markdown-title-body-options-no-convex-smoke.js`、`task436-local-markdown-open-document-external-change-smoke.js`、`task443-local-markdown-asset-upload-smoke.js`、`task451-local-markdown-conflict-resolution-ui-smoke.js`、`task452-local-search-index-browser-smoke.js`、`task453-local-folder-page-ai-changed-files-smoke.js`；WorkspacePath / ObjectIdentity runtime 消费统一改动补跑 `task524-workspace-object-identity-matrix-smoke.js`。`task452` 只覆盖普通本地搜索、settings API、tag/backlink API 和旧 local-index UI 不复活；资料库问答、PDF/Office/image source ingestion 与引用回跳改跑 LightRAG 脚本。
+- LightRAG 资料库：`task534-knowledge-rag-source-management-scope-smoke.js` 覆盖本地文件夹 source 加入资料库、registry 状态与范围管理；`task529-knowledge-rag-citation-resource-tab-smoke.js`、`task530-knowledge-rag-page-ai-final-answer-smoke.js` 覆盖资料库引用回到资源页与 Page AI 最终回答。旧 `task526-local-folder-ocr-api-smoke.js` / OCR sidecar 链路已退役并软归档；`/api/search/documents` 不作为 LightRAG、LiteParse、OCR sidecar 或 evidence.sqlite 的资料库问答 fallback。
 - local Markdown conflict regression：`task510-local-markdown-conflict-regression-group.js` 串联真实冲突、连续上传、新建页面、外部恢复、多 tab CAS 与上传 409 孤儿策略；可用 `MNOTE_CONFLICT_REGRESSION_TASKS=a.js,b.js` 做定点子集。
 - tree realtime / live cache：`task446-tree-rename-dual-browser-live-smoke.js`、`task447-tree-move-order-dual-browser-live-smoke.js`、`task448-tree-resync-recovery-dual-browser-smoke.js`、`task449-tree-sse-reconnect-snapshot-recovery-smoke.js`
 - 资源对象与 mindmap：`task455-local-folder-mindmap-clean-smoke.js`、`task456-resource-object-shell-sync-smoke.js`、`task166-mindmap-phase6-block-smoke.js`、`task167-mindmap-kmind-parity-smoke.js`、`task168-mindmap-put-validator-smoke.js`；Page AI mindmap skill / 资源生成改动补跑 `task503-mindmap-skill-capability-smoke.js`，真实 mindmap resource tab / Page AI target 改动补跑 `task525-page-ai-mindmap-resource-target-smoke.js`