fix: replace all remaining emoji with monochrome glyph constants

- trash.ts TYPE_ICONS map uses GLYPH_TYPE_* constants
- field-history.ts copy button uses GLYPH_COPY
- attachments-disclosure.ts thumbnail/icon uses GLYPH_TYPE_DOCUMENT
- settings.ts sync button uses GLYPH_SYNC
- document.ts thumb/sigblock/preview use GLYPH_TYPE_DOCUMENT + GLYPH_PREVIEW
- glyphs.ts adds GLYPH_COPY, GLYPH_SYNC, GLYPH_PREVIEW
- vault.ts adds GLYPH_DEVICES import + devices sidebar nav button

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

extension/src/popup/components/field-history.ts

@@ -3,6 +3,7 @@
 import { getState, setState, sendMessage, navigate, escapeHtml } from '../../shared/state';
 import { colorizePassword } from '../../shared/password-coloring';
 import type { FieldHistoryView } from '../../shared/types';
+import { GLYPH_COPY } from '../../shared/glyphs';
 
 function relativeTime(unixSec: number): string {
   const now = Math.floor(Date.now() / 1000);
@@ -75,7 +76,7 @@ export async function renderFieldHistory(app: HTMLElement): Promise<void> {
           ${isCurrent ? '<span class="history-entry__current">current</span>' : ''}
           <span>${isCurrent ? 'set' : 'changed'} ${relativeTime(timestamp)}</span>
         </div>
-        <button class="history-entry__copy" data-entry-copy="${escapeHtml(entryKey)}" title="Copy">📋</button>
+        <button class="history-entry__copy" data-entry-copy="${escapeHtml(entryKey)}" title="Copy">${GLYPH_COPY}</button>
       </div>
     `;
   }
@@ -140,7 +141,7 @@ export async function renderFieldHistory(app: HTMLElement): Promise<void> {
       const value = valueStore.get(key) ?? '';
       await navigator.clipboard.writeText(value);
       btn.textContent = '✓';
-      setTimeout(() => { btn.textContent = '📋'; }, 1500);
+      setTimeout(() => { btn.textContent = GLYPH_COPY; }, 1500);
     });
   });
 }