feat: Add TagRemovalZone component and refactor drag-drop for tag management

frontend/src/documents/components/TagRemovalZone.css

@@ -0,0 +1,31 @@
+.tag-removal-zone {
+    position: absolute;
+    bottom: 0;
+    left: 0;
+    right: 0;
+    height: 4rem;
+    background-color: var(--surface-subtle);
+    border-top: 2px dashed var(--border);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    color: var(--muted);
+    z-index: 6000002;
+    transition: all 0.2s ease;
+    pointer-events: all;
+    gap: 0.5rem;
+}
+
+.tag-removal-zone--drag-over {
+    height: 6rem;
+    background: linear-gradient(var(--surface-danger-subtle), var(--surface-danger-subtle)), var(--surface);
+    border-color: var(--danger);
+    color: var(--danger);
+}
+
+/* Ensure icon inherits color and overrides .icon class size */
+.tag-removal-zone__icon {
+    width: 60%;
+    height: 60%;
+    stroke: currentColor;
+}

frontend/src/documents/components/TagRemovalZone.tsx

@@ -0,0 +1,70 @@
+import React, { useEffect, useState } from 'react';
+import { subscribeToTagDrag } from '../features/tagging/tagTransfer';
+import { TrashIcon } from '../../components/icons';
+import './TagRemovalZone.css';
+
+const TagRemovalZone: React.FC = () => {
+    const [isVisible, setIsVisible] = useState(false);
+    const [isDragOver, setIsDragOver] = useState(false);
+    const [isInteractive, setIsInteractive] = useState(false);
+
+    useEffect(() => {
+        // Subscribe to global tag drag state.
+        // This avoids issues with event bubbling (stopPropagation) preventing window listeners.
+        return subscribeToTagDrag((state) => {
+            if (state.sourceDocId) {
+                setIsVisible(true);
+                // Delay interactivity to allow drag to start without immediate capture
+                // and to allow dropping on documents 'behind' the zone if done quickly
+                setTimeout(() => setIsInteractive(true), 200);
+            } else {
+                setIsVisible(false);
+                setIsDragOver(false);
+                setIsInteractive(false);
+            }
+        });
+    }, []);
+
+    const onDragOver = (event: React.DragEvent) => {
+        if (!isVisible || !isInteractive) return;
+        event.preventDefault();
+        event.stopPropagation(); // Exclusive zone
+        if (event.dataTransfer) {
+            event.dataTransfer.dropEffect = 'move';
+        }
+        setIsDragOver(true);
+    };
+
+    const onDragLeave = () => {
+        setIsDragOver(false);
+    };
+
+    const onDrop = (event: React.DragEvent) => {
+        if (!isInteractive) return;
+        event.preventDefault();
+        event.stopPropagation();
+        // Drop accepted. Browser sets dropEffect='move'.
+        // Source component's onDragEnd will handle the data removal.
+        setIsVisible(false);
+        setIsDragOver(false);
+        setIsInteractive(false);
+    };
+
+    if (!isVisible) {
+        return null;
+    }
+
+    return (
+        <div
+            className={`tag-removal-zone ${isDragOver ? 'tag-removal-zone--drag-over' : ''}`}
+            onDragOver={onDragOver}
+            onDragLeave={onDragLeave}
+            onDrop={onDrop}
+            style={{ pointerEvents: isInteractive ? 'all' : 'none' }}
+        >
+            <TrashIcon className="tag-removal-zone__icon" />
+        </div>
+    );
+};
+
+export default TagRemovalZone;

frontend/src/documents/data/useDocumentsWorkspace.ts

@@ -51,7 +51,6 @@ import usePasskeys from '../../settings/usePasskeys';
 import { resolveBreadcrumbs } from '../logic/breadcrumbs';
 import useWorkspaceSelectionSync from '../features/selection/useWorkspaceSelectionSync';
 import useWorkspaceViewData from './useWorkspaceViewData';
-import useWorkspaceDragDrop from '../interactions/useWorkspaceDragDrop';
 import { useManagementModals } from '../../app/useManagementModals';
 import { useAppDispatch, useAppState } from '../../lib/store/appState';
 import { listFolderContents } from '../../lib/api/apiClient';
@@ -926,9 +925,7 @@ const useDocumentsWorkspace = ({
     return () => window.removeEventListener('keydown', handleKeyDown);
   }, [settingsOpen]);
 
-  useWorkspaceDragDrop({
+
-    shellRef,
-  });
 
   const {
     detailPanelProps,

frontend/src/documents/features/tagging/tagTransfer.ts

@@ -44,11 +44,24 @@ interface ActiveDragState {
 }
 
 let activeDragState: ActiveDragState = { tagId: null, sourceDocId: null };
+const listeners = new Set<(state: ActiveDragState) => void>();
 
 export const getActiveDragState = (): ActiveDragState => activeDragState;
 
+export const subscribeToTagDrag = (callback: (state: ActiveDragState) => void): () => void => {
+  listeners.add(callback);
+  return () => {
+    listeners.delete(callback);
+  };
+};
+
+const notifyListeners = () => {
+  listeners.forEach((cb) => cb(activeDragState));
+};
+
 export const clearTagTransferData = (): void => {
   activeDragState = { tagId: null, sourceDocId: null };
+  notifyListeners();
 };
 
 export const writeTagTransferData = (
@@ -61,6 +74,7 @@ export const writeTagTransferData = (
     tagId: tag.id || null,
     sourceDocId: sourceDocId || null,
   };
+  notifyListeners();
 
   if (!dataTransfer) {
     return;

frontend/src/documents/interactions/useWorkspaceDragDrop.ts

@@ -1,80 +0,0 @@
-import { useEffect } from 'react';
-import type { MutableRefObject } from 'react';
-import {
-    isTagTransferEvent,
-    getActiveDragState,
-} from '../features/tagging/tagTransfer';
-
-interface UseWorkspaceDragDropArgs {
-    shellRef: MutableRefObject<HTMLElement | null>;
-}
-
-const useWorkspaceDragDrop = ({
-    shellRef,
-}: UseWorkspaceDragDropArgs) => {
-
-    useEffect(() => {
-        const host = shellRef.current;
-        if (!host) {
-            return;
-        }
-
-        // Allow drop on workspace (global app shell)
-        const handleTagDragOver = (event: DragEvent) => {
-            if (!isTagTransferEvent(event)) {
-                return;
-            }
-
-            const { sourceDocId } = getActiveDragState();
-
-            // Only allow "Move" (removal) if the tag came from a document
-            if (sourceDocId) {
-                event.preventDefault(); // Necessary to allow dropping
-                if (event.dataTransfer) {
-                    event.dataTransfer.dropEffect = 'move';
-                }
-            }
-        };
-
-        const handleTagDragEnter = (event: DragEvent) => {
-            if (!isTagTransferEvent(event)) {
-                return;
-            }
-            const { sourceDocId } = getActiveDragState();
-            if (sourceDocId) {
-                event.preventDefault();
-                if (event.dataTransfer) {
-                    event.dataTransfer.dropEffect = 'move';
-                }
-            }
-        };
-
-        const handleTagDrop = (event: DragEvent) => {
-            if (!isTagTransferEvent(event)) {
-                return;
-            }
-
-            const { sourceDocId } = getActiveDragState();
-
-            if (sourceDocId) {
-                // Consume the event so the browser reports 'move' back to the source
-                event.preventDefault();
-            }
-        };
-
-        // Use bubbling (false) so children can stopPropagation
-        host.addEventListener('dragenter', handleTagDragEnter, false);
-        host.addEventListener('dragover', handleTagDragOver, false);
-        host.addEventListener('drop', handleTagDrop, false);
-
-        return () => {
-            host.removeEventListener('dragenter', handleTagDragEnter, false);
-            host.removeEventListener('dragover', handleTagDragOver, false);
-            host.removeEventListener('drop', handleTagDrop, false);
-        };
-    }, [shellRef]);
-
-    return {};
-};
-
-export default useWorkspaceDragDrop;

frontend/src/documents/panel/DocumentsPanel.tsx

@@ -5,6 +5,7 @@ import React, {
   useRef,
   useEffect,
 } from 'react';
+import TagRemovalZone from '../components/TagRemovalZone';
 import { DocumentsList, DocumentsGrid } from '../DocumentsView';
 import type { ReactNode } from 'react';
 import type {
@@ -307,6 +308,7 @@ const DocumentsPanelInner: React.FC<DocumentsPanelInnerProps> = (props) => {
             onBreadcrumbClick={onBreadcrumbNavigate}
           />
           <div className="documents-panel-wrapper">
+            <TagRemovalZone />
             <section
               ref={scrollRef}
               className={`documents-panel documents-panel--view-${panelVariant}`}