Replace curated ~270 emoji subset with full Unicode set (1900+) via
unicode-emoji-json. Emoji search now works by English name (e.g.
"rocket" → 🚀). All emojis visible in continuous scroll with sticky
category headers and icon-based quick-nav tabs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Every note can now have an optional emoji icon (frontmatter `icon` field).
The icon is displayed in the editor header, note list, search results,
and Quick Open. Includes command palette commands "Set Note Icon" and
"Remove Note Icon", plus full test coverage (Vitest + Playwright).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>