[Feature]: Add --user parameter to install.sh for user-local installation (to ~/.local/bin)

[leganck]

1. Your usage scenarios?

I use the install.sh script in Coder workspaces, where only the current user's home directory (~) is persisted across workspace restarts.

System-wide directories (e.g., /usr/local/bin) are ephemeral and get reset after a workspace restart—this means tools installed to these paths are lost, forcing me to re-run the install script every time the workspace restarts.

Installing to ~/.local/bin (a standard user-local binary directory in the persisted home directory) would ensure the tool remains available after workspace restarts, but the current script only supports system-wide installation (requiring sudo/root and installing to non-persistent paths).

2. What is your expected outcome?

• Add a --user flag to install.sh. When used (e.g., ./install.sh --user):
  • The script installs the binary to ~/.local/bin (automatically create the directory if it does not exist).
  • Bypass sudo/root permission checks (since ~/.local/bin is within the user's writable home directory).
  • Ensure ~/.local/bin is added to the user's $PATH (if not already present) to make the tool accessible immediately.
• Keep the default behavior (install to system-wide paths like /usr/local/bin) when --user is not specified (preserve backward compatibility).