feat: Update zsh configs to support multiple Homebrew installations

feat #1: Update .zshenv to support multiple Homebrew installations

Added conditional checks in .zshenv to evaluate the Homebrew environment
based on the existence of the Homebrew binary in either the /opt/homebrew
or /usr/local/bin directories. This ensures compatibility with different
Homebrew installations.

feat #2: Improve Antigen sourcing logic in .zshrc

Updated the .zshrc configuration to include conditional sourcing for Antigen.
Checks for the existence of Antigen in two possible locations and provides
a message if not found, enhancing user experience and installation guidance.

home/.zshenv

@@ -1 +1,5 @@
-eval "$(/opt/homebrew/bin/brew shellenv)"
+if [ -x "/opt/homebrew/bin/brew" ]; then
+    eval "$(/opt/homebrew/bin/brew shellenv)"
+elif [ -x "/usr/local/bin/brew" ]; then
+    eval "$(/usr/local/bin/brew shellenv)"
+fi

home/.zshrc

@@ -67,9 +67,14 @@ ZSH_HIGHLIGHT_HIGHLIGHTERS=(main brackets pattern cursor)
 ###############
 ### Antigen ###
 ###############
-#source ~/bin/antigen.zsh
-#source /usr/local/share/antigen/antigen.zsh # brew install antigen
-source /opt/homebrew/share/antigen/antigen.zsh
+#brew install antigen
+if [ -f "/opt/homebrew/share/antigen/antigen.zsh" ]; then
+    source /opt/homebrew/share/antigen/antigen.zsh
+elif [ -f "/usr/local/share/antigen/antigen.zsh" ]; then
+    source /usr/local/share/antigen/antigen.zsh
+else
+    echo "Antigen not found. Please install antigen using: brew install antigen"
+fi
 
 # Load the oh-my-zsh's library.
 antigen use oh-my-zsh