Update install.sh to improve user prompts and remove redundant messages.

[rohitpaulk]

Note

Modernizes the installer and aligns CI.

• Switches install.sh to Bash with set -euo pipefail, adds colored/muted output, and ensures cleanup resets colors
• Streamlines download/install UX: muted curl progress, clearer sudo notes, and a concise success message with version
• Updates GitHub Actions to run bash install.sh on Linux (replacing dash -x)

^{Written by Cursor Bugbot for commit ee9f933. This will update automatically on new commits. Configure here.}

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is ON. A Cloud Agent has been kicked off to fix the reported issue.}

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Bugbot Autofix prepared a fix for the bug found in the latest run.

• ✅ Fixed: Non-POSIX echo -e used with #!/bin/sh shebang
  • Replaced all echo -e calls with printf '%b' or printf '%b\n' which is POSIX-compliant and correctly interprets backslash escape sequences on all sh implementations including dash.