build: add ASCII splash screen to Build.sh for better onboarding UX

[Divinesoumyadip]

First impressions matter. When a new contributor runs the build script, they are immediately hit with a wall of dense system text. It feels intimidating and purely functional.
By adding a clean, cyan OpenROAD splash screen at the very start of the script execution, we instantly make the CLI feel more professional, welcoming, and polished.
While primarily cosmetic, this directly aligns with the "vibe" of the Onboarding Simplification initiative. It signals to new developers that the build environment is well-maintained and user-centric before the compilation even begins.

[gemini-code-assist]

Code Review

This pull request introduces an ASCII art splash screen to the Build.sh script, aiming to improve the onboarding experience. The implementation correctly handles color codes by checking if the output is a terminal. However, there's a potential issue where the script could fail on systems without the tput command due to set -e being enabled. I've provided a suggestion to add a check for tput to make the script more robust. The remaining changes are minor formatting adjustments.

[gemini-code-assist]

The script uses tput to set terminal colors, but it doesn't check if the tput command is available. With set -e active, the script will exit with an error if tput is not found. To improve robustness, it's best to verify the command exists before using it.

Suggested change

	if [[ -t 1 ]]; then
	if [[ -t 1 ]] && command -v tput >/dev/null; then

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[maliberty]

The graphics are off