UX: Simplify icon ID format

## Enhancement Request
Icon IDs are unnecessarily long and complex, making debugging and data management difficult.

## Current State
- Very long UUID-style IDs
- Hard to work with manually
- Overkill for this application

## Suggested Solution
- Shorter IDs (8-12 characters)
- Human-readable prefixes (e.g., 'icon_12345')
- Or simple incremental IDs

## Priority
Low - backend improvement