feat(editor): support markdown shortcuts for block types (#207)

[zacharias-ona]

Closes #207

What

Adds inline markdown shortcuts to the Lexical editor. Typing standard markdown prefixes at the start of a line now converts to the corresponding block type:

Shortcut	Result
#	Heading 1
##	Heading 2
###	Heading 3
>	Blockquote
---	Horizontal rule
- or *	Bullet list
1.	Numbered list
```	Code block

How

Added MarkdownShortcutPlugin from @lexical/react/LexicalMarkdownShortcutPlugin to the editor, configured with the existing MARKDOWN_TRANSFORMERS array from markdown-utils.ts. No new dependencies — the plugin is already included in the @lexical/react package.

Testing

• Static analysis tests verify the plugin is included and transformers cover all required shortcut types
• pnpm lint && pnpm typecheck && pnpm test all pass (252 tests)

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
memo	Ready	Preview, Comment	Apr 17, 2026 11:36pm

[zacharias-ona]

✅ UI verification passed — design spec compliance confirmed.

Static analysis: No design spec violations. This PR adds MarkdownShortcutPlugin (a behavioral Lexical plugin) and imports MARKDOWN_TRANSFORMERS. No colors, typography, spacing, borders, or layout changes were introduced.

Visual verification: Playwright screenshots of the editor page (desktop 1280×800 dark mode + mobile 375×812) show no regressions — sidebar, editor layout, placeholder text, and mobile responsiveness all render correctly.

[zacharias-ona]

✅ Post-merge verification passed.

E2E suite: 57/57 tests passed against https://memo.software-factory.dev

Ad-hoc smoke tests:

• ✅ Landing page — loaded, has title
• ✅ Sign-in page — rendered with email input
• ✅ Health endpoint — returned OK
• ✅ Authenticated login flow — signed in, redirected to workspace
• ✅ Console errors — none (unauthenticated or authenticated)

Skipped:

• /dashboard (route does not exist — 404)
• Editor navigation via sidebar page button (no page buttons with timestamps found in test workspace)