Full DMS: folders + ACLs, versioning, trash, bulk ops, preview, smart folders

Rebuild the dashboard as a Drive-style document management system on top of
the existing CaveauAI hybrid RAG pipeline.

Backend:
- 5 migrations (versions, trash soft-delete, saved searches, categories, audit)
- DMS helpers (folder ACL walker, disk storage, audit, version snapshot,
  XLSX/PPTX/HTML/CSV/MD extractors)
- New APIs: folders, document-versions, trash, bulk, preview, saved-searches,
  categories, diagnostics
- Extended APIs: documents (folder_id, soft-delete, ACL filter, sort),
  upload (9 file types, version-collision detection with replace/new/keep-both,
  disk persistence), chat-stream (folder scoping + graph related-documents)
- 30-day trash purge cron with Qdrant + disk + graph cleanup

Frontend:
- Drive-style two-pane browser with folder tree, drag-drop, bulk-action bar,
  right-click context menu, multi-select
- New pages: folders (tree + per-folder ACL editor), trash (restore/purge)
- Extended pages: upload (folder picker, version-collision modal, 9 file
  type chips), document (Preview/Versions/Permissions tabs with PDF.js +
  mammoth.js + audio), index (DMS KPIs + activity feed), settings (live
  diagnostics ping MariaDB/Qdrant/LiteLLM/FalkorDB/disk), chat (folder
  scope chips + related-authorities chips)
- New CSS (dms.css) + JS bundle (dms.js) exposing window.DBN_DMS
- Sidebar nav adds Folders + Trash items

All routes return HTTP 200 in local smoke test; all 32 files lint clean.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

migrations/dbn-dms/002_dbn_dms_trash.sql

@@ -0,0 +1,34 @@
+-- DBN DMS migration 002 — soft-delete trash
+-- Adds deleted_at / deleted_by columns to client_documents and client_folders.
+
+-- client_documents.deleted_at
+SET @col_exists := (
+  SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+  WHERE TABLE_SCHEMA = DATABASE()
+    AND TABLE_NAME = 'client_documents' AND COLUMN_NAME = 'deleted_at'
+);
+SET @sql := IF(@col_exists = 0,
+  'ALTER TABLE client_documents
+     ADD COLUMN deleted_at DATETIME NULL AFTER updated_at,
+     ADD COLUMN deleted_by INT UNSIGNED NULL AFTER deleted_at,
+     ADD KEY idx_deleted (deleted_at)',
+  'SELECT 1');
+PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;
+
+-- client_folders.deleted_at (folders table may not exist if migration 119 hasn't run; guard table too)
+SET @tbl_exists := (
+  SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES
+  WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = 'client_folders'
+);
+SET @col_exists := IF(@tbl_exists = 0, 1,
+  (SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS
+   WHERE TABLE_SCHEMA = DATABASE()
+     AND TABLE_NAME = 'client_folders' AND COLUMN_NAME = 'deleted_at')
+);
+SET @sql := IF(@tbl_exists = 1 AND @col_exists = 0,
+  'ALTER TABLE client_folders
+     ADD COLUMN deleted_at DATETIME NULL,
+     ADD COLUMN deleted_by INT UNSIGNED NULL,
+     ADD KEY idx_deleted (deleted_at)',
+  'SELECT 1');
+PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;