feat: soft-delete and undo/restore for local-workspace items

Backend:
- DELETE /api/local-workspace/items/{id} now soft-deletes (sets deleted_at
  instead of hard DELETE) — items go to trash, not permanently gone
- New POST /api/local-workspace/items/{id}/restore to undo a delete
- _load_workspace_pages() and _load_children() now filter deleted_at IS NULL
  so soft-deleted items disappear from sidebar and tree queries

Frontend:
- undoDelete() now calls the restore API per item (single or bulk)
- bulkDelete() now shows the same undo banner as context menu delete
- All delete paths (ctxMenu, bulk, modal) use the same soft-delete + undo flow

app/routers/board.py

@@ -172,7 +172,7 @@ def _load_workspace_pages(ws_cookie: str) -> list:
         ws_id = int(ws_cookie)
         with get_conn() as conn:
             rows = conn.execute(
-                "SELECT id, title, parent_section, content_format FROM pages WHERE workspace_id=? AND parent_id IS NULL ORDER BY created_at DESC",
+                "SELECT id, title, parent_section, content_format FROM pages WHERE workspace_id=? AND parent_id IS NULL AND deleted_at IS NULL ORDER BY created_at DESC",
                 (ws_id,),
             ).fetchall()
         items = []
@@ -197,7 +197,7 @@ def _load_children(parent_id: int) -> list:
     """Recursively load children of a page."""
     with get_conn() as conn:
         rows = conn.execute(
-            "SELECT id, title, parent_section, content_format FROM pages WHERE parent_id=? ORDER BY created_at",
+            "SELECT id, title, parent_section, content_format FROM pages WHERE parent_id=? AND deleted_at IS NULL ORDER BY created_at",
             (parent_id,),
         ).fetchall()
     children = []

app/routers/dashboard.py

@@ -837,21 +837,25 @@ async def rename_local_workspace_item(request: Request, item_id: int):
 
 @router.delete("/api/local-workspace/items/{item_id:int}")
 async def delete_local_workspace_item(request: Request, item_id: int):
-    """Delete a file (and its children). Also removes uploaded file from disk."""
-    import json
-    from pathlib import Path
+    """Soft-delete a file/folder (sets deleted_at)."""
+    from datetime import datetime
     with get_conn() as conn:
-        # Check if it's a file-type page with a disk file
-        row = conn.execute("SELECT content, content_format FROM pages WHERE id=?", (item_id,)).fetchone()
-        if row and row["content_format"] == "file":
-            try:
-                meta = json.loads(row["content"])
-                fp = Path(f"/data/{meta['file_path']}")
-                if fp.exists():
-                    fp.unlink()
-            except Exception:
-                pass
-        conn.execute("DELETE FROM pages WHERE id=? OR parent_id=?", (item_id, item_id))
+        conn.execute(
+            "UPDATE pages SET deleted_at=? WHERE id=? AND deleted_at IS NULL",
+            (datetime.utcnow().isoformat(), item_id),
+        )
+        conn.commit()
+    return {"status": "ok"}
+
+
+@router.post("/api/local-workspace/items/{item_id:int}/restore")
+async def restore_local_workspace_item(request: Request, item_id: int):
+    """Restore a soft-deleted file/folder."""
+    with get_conn() as conn:
+        conn.execute(
+            "UPDATE pages SET deleted_at=NULL WHERE id=?",
+            (item_id,),
+        )
         conn.commit()
     return {"status": "ok"}