feat(ext/shared): glyph constants module for unified icon language

Centralizes the unicode glyphs used by sidebar nav and form action buttons
so popup and fullscreen surfaces stay in sync. Includes the REQUIRED_PILL
snippet used to replace the trailing-asterisk required-field marker.

Plan 2026-04-30 fullscreen UX phase 1 task 1.

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

extension/src/shared/__tests__/glyphs.test.ts

@@ -0,0 +1,21 @@
+import { describe, it, expect } from 'vitest';
+import * as glyphs from '../glyphs';
+
+describe('glyphs', () => {
+  it('exports the documented glyph constants', () => {
+    expect(glyphs.GLYPH_REVEAL).toBe('⊙');
+    expect(glyphs.GLYPH_HIDE).toBe('⊘');
+    expect(glyphs.GLYPH_GENERATE).toBe('↻');
+    expect(glyphs.GLYPH_FILL_FROM_TAB).toBe('⤓');
+    expect(glyphs.GLYPH_QR).toBe('◫');
+    expect(glyphs.GLYPH_MONO).toBe('≡');
+    expect(glyphs.GLYPH_TRASH).toBe('▦');
+    expect(glyphs.GLYPH_DEVICES).toBe('⌬');
+    expect(glyphs.GLYPH_SETTINGS).toBe('⚙');
+    expect(glyphs.GLYPH_LOCK).toBe('⏻');
+  });
+
+  it('exports REQUIRED_PILL as an HTML snippet', () => {
+    expect(glyphs.REQUIRED_PILL).toBe('<span class="req-pill">required</span>');
+  });
+});

extension/src/shared/glyphs.ts

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+//
+// Unicode glyph constants used across popup and fullscreen surfaces. All
+// glyphs are monochrome unicode (no emoji) so they render identically in the
+// codebase's monospace font. Pair each button glyph with a `title=` tooltip
+// at the call site for accessibility — the constants here are the visual,
+// not the affordance.
+
+export const GLYPH_REVEAL        = '⊙';   // password reveal toggle (hidden state)
+export const GLYPH_HIDE          = '⊘';   // password reveal toggle (revealed state)
+export const GLYPH_GENERATE      = '↻';   // password / passphrase generate
+export const GLYPH_FILL_FROM_TAB = '⤓';   // pull URL from active browser tab
+export const GLYPH_QR            = '◫';   // paste / upload QR image (TOTP)
+export const GLYPH_MONO          = '≡';   // toggle notes monospace font
+
+export const GLYPH_TRASH         = '▦';   // sidebar trash nav
+export const GLYPH_DEVICES       = '⌬';   // sidebar devices nav
+export const GLYPH_SETTINGS      = '⚙';   // sidebar settings nav
+export const GLYPH_LOCK          = '⏻';   // sidebar lock nav
+
+/// Inline HTML snippet for the required-field pill. Use after a label's text:
+///   `<label class="label" for="f-title">title ${REQUIRED_PILL}</label>`
+export const REQUIRED_PILL = '<span class="req-pill">required</span>';