Issue/29 lnk alias

[gowtham0992]

Fixes the installed CLI command collision reported in #29 by moving the user-facing wrapper from link to lnk.

What Changed

• Installers now create lnk instead of link.
• Existing Link-owned link wrappers are removed safely.
• Existing non-Link link binaries are not overwritten.
• Homebrew formula now installs/tests lnk.
• Generated follow-up commands are mode-aware:
  • installed users see lnk ...
  • source-checkout users see python .../link.py ...
• Fresh installer wiki setup now runs Link’s repair/init path instead of copying the repo sample index, so lnk health starts clean.
• Tests updated for shell, PowerShell, Homebrew, source-checkout, and installed-wrapper guidance.