[UI/UX] Enhance CLI Aesthetics: Modernize Logs & Banner

### Goal
Upgrade the visual appearance of STOV to make it look more like a modern, professional CLI tool.

### The Task
Currently, the tool uses standard `[INFO]` and `[ERROR]` tags. We want to replace these with cleaner symbols or better color schemes to improve the user experience.

**Requirements:**
1. **Modernize Logs:** Update the `log_info` and `log_error` functions to use modern symbols (e.g., `➜`, `✔`, `✖`, `>>`) instead of text brackets.
2. **Enhance Banner:** Improve the ASCII art or color scheme of the startup banner.
3. **Consistency:** Ensure the new style is consistent across the entire application run.

### Files to Edit
- `src/utils.rs` (Logging logic)
- `src/main.rs` (Banner display)

This project uses the `colored` crate for terminal styling.