Add real-time GitHub sync to installers and sync script

Interactive installer (interactive-install-claude.sh):
- Add fetch_latest_agents() function to check GitHub for updates
- Clone latest agents from contains-studio/agents before installing
- Update local agents directory with upstream changes
- Gracefully fallback to local agents if GitHub fetch fails
- Call fetch_latest_agents() before install_agents() in main flow

Sync script (sync-agents.sh):
- Add REPO_AGENTS_DIR environment variable support
- Automatically update repository agents directory when syncing
- Keep installer agents in sync with Claude Code agents

This ensures users always get the latest agents from upstream GitHub
while maintaining customizations in the local repository.

interactive-install-claude.sh

@@ -594,6 +594,49 @@ create_directories() {
     log_success "Directories created"
 }
 
+fetch_latest_agents() {
+    log_info "Checking for agent updates from GitHub..."
+
+    local GITHUB_REPO="https://github.com/contains-studio/agents"
+    local TEMP_AGENT_DIR="/tmp/claude-agents-latest-$RANDOM"
+    local UPDATE_FOUND=false
+
+    # Create temp directory
+    mkdir -p "$TEMP_AGENT_DIR"
+
+    # Try to clone using git
+    if command -v git &> /dev/null; then
+        if git clone --depth 1 --quiet "$GITHUB_REPO" "$TEMP_AGENT_DIR" 2>/dev/null; then
+            UPDATE_FOUND=true
+            log_success "Fetched latest agents from GitHub"
+
+            # Copy updated agents to source directory
+            for category in engineering marketing product studio-operations project-management testing design bonus; do
+                if [ -d "$TEMP_AGENT_DIR/$category" ]; then
+                    mkdir -p "$SCRIPT_DIR/agents/$category"
+                    cp -f "$TEMP_AGENT_DIR/$category"/*.md "$SCRIPT_DIR/agents/$category/" 2>/dev/null || true
+                fi
+            done
+
+            # Update README if present
+            if [ -f "$TEMP_AGENT_DIR/README.md" ]; then
+                cp -f "$TEMP_AGENT_DIR/README.md" "$SCRIPT_DIR/agents/README.md" 2>/dev/null || true
+            fi
+
+            log_info "Local agents updated from GitHub"
+        else
+            log_warning "Failed to fetch from GitHub (using local agents)"
+        fi
+    else
+        log_warning "Git not found (using local agents)"
+    fi
+
+    # Cleanup
+    rm -rf "$TEMP_AGENT_DIR"
+
+    return 0
+}
+
 install_agents() {
     if [ $SELECTED_AGENTS -eq 0 ]; then
         return
@@ -1055,6 +1098,7 @@ perform_installation() {
     echo ""
 
     create_directories
+    fetch_latest_agents
     install_agents
     install_settings
     install_local_settings