fix: remove SSH fallback for GitHub cloning, use HTTPS only

GitHub Clone Simplification - Complete:
✅ SSH FALLBACK REMOVED: Simplified repository cloning to use HTTPS only
- setup.sh: Removed git@github.com SSH fallback that requires SSH keys
- Reason: Most users don't have GitHub SSH keys or accounts
- Impact: More accessible setup for all users

✅ BEFORE vs AFTER:
❌ Before: HTTPS with SSH fallback
   git clone https://github.com/aitbc/aitbc.git aitbc || {
       git clone git@github.com:aitbc/aitbc.git aitbc || error "Failed to clone repository"
   }
   - Required SSH keys for fallback
   - GitHub account needed for SSH access
   - Complex error handling

✅ After: HTTPS only
   git clone https://github.com/aitbc/aitbc.git aitbc || error "Failed to clone repository"
   - No SSH keys required
   - Public repository access
   - Simple and reliable
   - Works for all users

✅ ACCESSIBILITY IMPROVEMENTS:
🌐 Public Access: HTTPS works for everyone without authentication
🔑 No SSH Keys: No need to generate and configure SSH keys
📦 No GitHub Account: Works without personal GitHub account
🚀 Simpler Setup: Fewer configuration requirements
🎯 Universal Compatibility: Works on all systems and networks

✅ TECHNICAL BENEFITS:
✅ Reliability: HTTPS is more reliable across different networks
✅ Security: HTTPS is secure and appropriate for public repositories
✅ Simplicity: Single method, no complex fallback logic
✅ Debugging: Easier to troubleshoot connection issues
✅ Firewalls: HTTPS works through most firewalls and proxies

✅ USER EXPERIENCE:
✅ Lower Barrier: No SSH setup required
✅ Faster Setup: Fewer prerequisites
✅ Clear Errors: Single error message for failures
✅ Documentation: Simpler to document and explain
✅ Consistency: Same method as documented in README

✅ JUSTIFICATION:
📦 Public Repository: AITBC is public, no authentication needed
🔧 Setup Script: Should work out-of-the-box for maximum accessibility
🌐 Broad Audience: Open source project should be easy to set up
🎯 Simplicity: Remove unnecessary complexity
📚 Documentation: Matches public repository access methods

RESULT: Successfully simplified GitHub cloning to use HTTPS only, removing SSH key requirements and making the setup accessible to all users without GitHub accounts or SSH configuration.

setup.sh

@@ -76,10 +76,7 @@ clone_repo() {
     
     # Clone repository
     cd /opt
-    git clone https://github.com/aitbc/aitbc.git aitbc || {
-        # Try alternative GitHub URL
-        git clone git@github.com:aitbc/aitbc.git aitbc || error "Failed to clone repository"
-    }
+    git clone https://github.com/aitbc/aitbc.git aitbc || error "Failed to clone repository"
     
     cd /opt/aitbc
     success "Repository cloned successfully"