refactor(ui): replace emoji icons with lucide-react icon library

[mpiton]

Refactor Request

Problem

The app uses Unicode emoji characters (👀 ❌ ✅) as icons. Emoji rendering varies significantly across operating systems, browsers, and WebView versions, leading to inconsistent visual appearance.

Current Usage

• Review request indicators: 👀
• CI failure: ❌
• PR approved: ✅
• Various status indicators in notifications and activity feed

Proposed Solution

Migrate to lucide-react — a lightweight, tree-shakeable icon library with consistent SVG rendering:

npm install lucide-react

Replacement mapping:

Current	Lucide equivalent
👀	<Eye />
❌	<XCircle /> or <CircleX />
✅	<CheckCircle /> or <CircleCheck />

Benefits

• Consistent rendering across all platforms
• Customizable size, color, stroke width
• Tree-shakeable (only bundled icons are included)
• ~0.5KB per icon

Files to Modify

• Components using emoji icons (grep for emoji patterns)
• src/components/Toast/Toast.tsx — notification icons
• Various card and status components