feat: Make it easier to handle multiple tags

- Tags can now be removed straight from the email header
- Tagging control now allows the user to (de)select multiple tags in one go

components/email/__tests__/tag-badge.test.tsx

@@ -0,0 +1,41 @@
+import { render, screen, fireEvent } from '@testing-library/react';
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { TagBadge } from '../tag-badge';
+import { useSettingsStore, type KeywordDefinition } from '@/stores/settings-store';
+
+const TAGS: KeywordDefinition[] = [
+  { id: 'work', label: 'Work', color: 'blue' },
+  { id: 'work/clients', label: 'Clients', color: 'green' },
+];
+
+describe('TagBadge', () => {
+  beforeEach(() => {
+    useSettingsStore.setState({ emailKeywords: TAGS, nestedTags: true });
+  });
+
+  it('names the tag by its full path', () => {
+    render(<TagBadge tagId="work/clients" variant="badge" />);
+    expect(screen.getByText('Work/Clients')).toBeInTheDocument();
+  });
+
+  it('names a tag it has no definition for by its id', () => {
+    render(<TagBadge tagId="from-elsewhere" variant="badge" />);
+    expect(screen.getByText('from-elsewhere')).toBeInTheDocument();
+  });
+
+  it('offers removal only when asked to', () => {
+    const onRemove = vi.fn();
+    const { rerender } = render(<TagBadge tagId="work" variant="badge" />);
+    expect(screen.queryByRole('button')).not.toBeInTheDocument();
+
+    rerender(<TagBadge tagId="work" variant="badge" onRemove={onRemove} />);
+    fireEvent.click(screen.getByRole('button', { name: 'remove_tag' }));
+    expect(onRemove).toHaveBeenCalledOnce();
+  });
+
+  it('leaves the dot alone, having nowhere to put the control', () => {
+    render(<TagBadge tagId="work" variant="dot" onRemove={() => {}} />);
+    expect(screen.queryByRole('button')).not.toBeInTheDocument();
+    expect(screen.getByLabelText('Work')).toBeInTheDocument();
+  });
+});

components/email/__tests__/tag-picker.test.tsx

@@ -53,12 +53,28 @@ describe('TagPicker', () => {
     expect(onToggle).toHaveBeenCalledWith('work/clients');
   });
 
-  it('offers the clear-all row only while something is applied', () => {
-    const { rerender } = render(<TagPicker selectedIds={[]} onToggle={() => {}} onClearAll={() => {}} />);
-    expect(screen.queryByText('remove_tag')).not.toBeInTheDocument();
+  it('lists a tag it has no definition for, so it can be taken off', () => {
+    const onToggle = vi.fn();
+    const { rerender } = render(<TagPicker selectedIds={['from-elsewhere']} onToggle={onToggle} />);
 
-    rerender(<TagPicker selectedIds={['work']} onToggle={() => {}} onClearAll={() => {}} />);
-    expect(screen.getByText('remove_tag')).toBeInTheDocument();
+    const row = screen.getByText('from-elsewhere').closest('button')!;
+    expect(row).toHaveAttribute('aria-checked', 'true');
+
+    fireEvent.click(row);
+    expect(onToggle).toHaveBeenCalledWith('from-elsewhere');
+
+    // Nothing but the message says it exists, so deselecting is the last of it.
+    rerender(<TagPicker selectedIds={[]} onToggle={onToggle} />);
+    expect(screen.queryByText('from-elsewhere')).not.toBeInTheDocument();
+  });
+
+  it('counts undefined tags towards the filter box, and matches them', () => {
+    const strays = Array.from({ length: 8 }, (_, i) => `stray-${i}`);
+    const { container } = render(<TagPicker selectedIds={strays} onToggle={() => {}} />);
+
+    fireEvent.change(screen.getByLabelText('tag_filter_placeholder'), { target: { value: 'stray-3' } });
+    expect(within(container).getByText('stray-3')).toBeInTheDocument();
+    expect(within(container).queryByText('Work')).not.toBeInTheDocument();
   });
 
   it('hides the filter box until the list is long enough to need one', () => {