docs: Add API connection debugging documentation and progress update

Added comprehensive debugging tools and documentation for API connection issues.

Changes:
- Created test-api-connection.sh - Automated diagnostic script
- Created DEBUGGING_GUIDE.md - Step-by-step debugging guide
- Created API_CONNECTION_FIX_SUMMARY.md - Complete fix summary
- Updated progress.md with API connection debugging enhancement entry

These tools help diagnose and resolve frontend-backend connection issues.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

test-api-connection.sh

@@ -0,0 +1,119 @@
+#!/bin/bash
+
+# ColaFlow API Connection Test Script
+# This script helps diagnose API connection issues
+
+echo "============================================"
+echo "ColaFlow API Connection Diagnostic Test"
+echo "============================================"
+echo ""
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m' # No Color
+
+# Test 1: Check if backend is running on port 5167
+echo "Test 1: Checking if backend is running on port 5167..."
+if curl -s -o /dev/null -w "%{http_code}" http://localhost:5167 > /dev/null 2>&1; then
+    echo -e "${GREEN}✓ Backend is responding on port 5167${NC}"
+else
+    echo -e "${RED}✗ Backend is NOT responding on port 5167${NC}"
+    echo "  → Solution: Start the backend server"
+    echo "     cd ColaFlow.Api && dotnet run"
+fi
+echo ""
+
+# Test 2: Check API health endpoint
+echo "Test 2: Checking API health endpoint..."
+HEALTH_STATUS=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:5167/api/v1/health 2>&1)
+if [ "$HEALTH_STATUS" = "200" ]; then
+    echo -e "${GREEN}✓ API health endpoint is working${NC}"
+elif [ "$HEALTH_STATUS" = "404" ]; then
+    echo -e "${YELLOW}⚠ API health endpoint not found (404)${NC}"
+    echo "  → This is OK if health endpoint is not implemented"
+elif [ "$HEALTH_STATUS" = "000" ]; then
+    echo -e "${RED}✗ Cannot connect to API (Connection refused)${NC}"
+    echo "  → Solution: Start the backend server"
+else
+    echo -e "${YELLOW}⚠ Unexpected status code: $HEALTH_STATUS${NC}"
+fi
+echo ""
+
+# Test 3: Check projects endpoint
+echo "Test 3: Checking projects endpoint..."
+PROJECTS_STATUS=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:5167/api/v1/projects 2>&1)
+if [ "$PROJECTS_STATUS" = "200" ]; then
+    echo -e "${GREEN}✓ Projects endpoint is working${NC}"
+    PROJECTS_DATA=$(curl -s http://localhost:5167/api/v1/projects)
+    echo "  Response: $PROJECTS_DATA"
+elif [ "$PROJECTS_STATUS" = "401" ]; then
+    echo -e "${YELLOW}⚠ Projects endpoint requires authentication (401)${NC}"
+    echo "  → This is OK, authentication is working"
+elif [ "$PROJECTS_STATUS" = "404" ]; then
+    echo -e "${RED}✗ Projects endpoint not found (404)${NC}"
+    echo "  → Check backend routing configuration"
+elif [ "$PROJECTS_STATUS" = "000" ]; then
+    echo -e "${RED}✗ Cannot connect to API (Connection refused)${NC}"
+    echo "  → Solution: Start the backend server"
+else
+    echo -e "${YELLOW}⚠ Unexpected status code: $PROJECTS_STATUS${NC}"
+fi
+echo ""
+
+# Test 4: Check if frontend is running
+echo "Test 4: Checking if frontend is running on port 3000..."
+FRONTEND_STATUS=$(curl -s -o /dev/null -w "%{http_code}" http://localhost:3000 2>&1)
+if [ "$FRONTEND_STATUS" = "200" ]; then
+    echo -e "${GREEN}✓ Frontend is running on port 3000${NC}"
+elif [ "$FRONTEND_STATUS" = "000" ]; then
+    echo -e "${RED}✗ Frontend is NOT running on port 3000${NC}"
+    echo "  → Solution: Start the frontend server"
+    echo "     cd colaflow-web && npm run dev"
+else
+    echo -e "${YELLOW}⚠ Unexpected status code: $FRONTEND_STATUS${NC}"
+fi
+echo ""
+
+# Test 5: Check .env.local configuration
+echo "Test 5: Checking .env.local configuration..."
+if [ -f "colaflow-web/.env.local" ]; then
+    echo -e "${GREEN}✓ .env.local file exists${NC}"
+
+    # Check if API URL is configured
+    if grep -q "NEXT_PUBLIC_API_URL" colaflow-web/.env.local; then
+        API_URL=$(grep "NEXT_PUBLIC_API_URL" colaflow-web/.env.local | cut -d '=' -f 2)
+        echo "  Configured API URL: $API_URL"
+
+        if [ "$API_URL" = "http://localhost:5167/api/v1" ]; then
+            echo -e "${GREEN}✓ API URL is correctly configured${NC}"
+        else
+            echo -e "${YELLOW}⚠ API URL might be incorrect${NC}"
+            echo "  Expected: http://localhost:5167/api/v1"
+            echo "  Found: $API_URL"
+        fi
+    else
+        echo -e "${RED}✗ NEXT_PUBLIC_API_URL not found in .env.local${NC}"
+        echo "  → Solution: Add NEXT_PUBLIC_API_URL=http://localhost:5167/api/v1"
+    fi
+else
+    echo -e "${RED}✗ .env.local file not found${NC}"
+    echo "  → Solution: Create .env.local with NEXT_PUBLIC_API_URL=http://localhost:5167/api/v1"
+fi
+echo ""
+
+# Summary
+echo "============================================"
+echo "Summary"
+echo "============================================"
+echo ""
+echo "Next steps:"
+echo "1. If backend is not running: cd ColaFlow.Api && dotnet run"
+echo "2. If frontend is not running: cd colaflow-web && npm run dev"
+echo "3. If .env.local is missing: Create it with NEXT_PUBLIC_API_URL=http://localhost:5167/api/v1"
+echo "4. After starting services, open http://localhost:3000/projects"
+echo "5. Press F12 and check Console and Network tabs for detailed errors"
+echo ""
+echo "For more details, see DEBUGGING_GUIDE.md"
+echo ""