refactor: remove legacy parser system and migrate to unified engine

- Remove internal/parser package and all legacy ID generation logic
- Update enhancer and auto_enhancer to use unified engine functions
- Migrate utility functions (FindViableChildren, HasEditableContent) to engine
- Create stub enhancer implementation that uses unified engine architecture
- Ensure all enhancement workflows now go through single unified system
- Remove parser dependencies and consolidate content processing logic

This completes the cleanup phase - all components now use unified engine
instead of fragmented ID generation systems.

test_unified_engine.sh

@@ -0,0 +1,69 @@
+#!/bin/bash
+
+# Test script for unified content engine architecture
+echo "🔧 Testing Unified Content Engine Architecture"
+echo
+
+# Test data
+HTML_MARKUP='<h2 class="hero-title">Welcome to Our Site</h2>'
+SITE_ID="demo"
+FILE_PATH="index.html"
+CONTENT_VALUE="Welcome to Our Amazing Website"
+CONTENT_TYPE="text"
+
+echo "📝 Test Data:"
+echo "  HTML Markup: $HTML_MARKUP" 
+echo "  Site ID: $SITE_ID"
+echo "  File Path: $FILE_PATH"
+echo "  Content: $CONTENT_VALUE"
+echo
+
+# Create JSON payload
+JSON_PAYLOAD=$(cat <<EOF
+{
+    "html_markup": "$HTML_MARKUP",
+    "file_path": "$FILE_PATH", 
+    "site_id": "$SITE_ID",
+    "value": "$CONTENT_VALUE",
+    "type": "$CONTENT_TYPE"
+}
+EOF
+)
+
+echo "🌐 Testing API endpoint..."
+echo "POST http://localhost:8080/api/content"
+echo
+
+# Test the API
+RESPONSE=$(curl -s -X POST \
+  http://localhost:8080/api/content \
+  -H "Content-Type: application/json" \
+  -H "Authorization: Bearer mock-token" \
+  -d "$JSON_PAYLOAD" 2>/dev/null)
+
+if [ $? -eq 0 ] && [ -n "$RESPONSE" ]; then
+    echo "✅ API Response:"
+    echo "$RESPONSE" | jq '.' 2>/dev/null || echo "$RESPONSE"
+    echo
+    
+    # Extract ID from response if possible
+    CONTENT_ID=$(echo "$RESPONSE" | jq -r '.id' 2>/dev/null)
+    if [ "$CONTENT_ID" != "null" ] && [ -n "$CONTENT_ID" ]; then
+        echo "🎯 Generated Content ID: $CONTENT_ID"
+        echo
+        
+        # Test retrieval
+        echo "🔍 Testing content retrieval..."
+        GET_RESPONSE=$(curl -s "http://localhost:8080/api/content/$CONTENT_ID?site_id=$SITE_ID" 2>/dev/null)
+        echo "GET Response:"
+        echo "$GET_RESPONSE" | jq '.' 2>/dev/null || echo "$GET_RESPONSE"
+    fi
+else
+    echo "❌ API Request Failed or Server Not Running"
+    echo "Response: $RESPONSE"
+    echo
+    echo "💡 Start the server with: just dev"
+fi
+
+echo
+echo "🏁 Test Complete"