Fix file upload issues and add Swagger UI API documentation

✅ Frontend File Upload Fixes:
- Fixed file upload reset issue - can now upload multiple files without page reload
- Added 'Change File' and 'Upload Another Image' buttons for better UX
- Fixed double-click file selection issue with proper event handling
- Improved drag & drop functionality with proper event propagation
- Added visual feedback for file selection and processing states

✅ Swagger UI API Documentation:
- Created api_docs.py with comprehensive Swagger UI documentation
- Added Flask-RESTX for professional API documentation interface
- Documented all 3 detection endpoints with request/response models
- Added health check endpoint documentation
- Included detailed parameter descriptions and example responses
- Available at http://localhost:5003/docs/ for interactive API testing

✅ Enhanced User Experience:
- Seamless file upload workflow without page reloads
- Clear visual indicators for file selection and processing
- Professional API documentation for developers and QA testing
- Consistent 80% confidence threshold across all interfaces

✅ Technical Improvements:
- Better event handling for file inputs and drag & drop
- Proper cleanup of uploaded files and UI state
- Comprehensive error handling and user feedback
- Interactive API documentation with live testing capabilities

static/script.js

@@ -23,7 +23,14 @@ function setupEventListeners() {
     uploadArea.addEventListener('dragover', handleDragOver);
     uploadArea.addEventListener('dragleave', handleDragLeave);
     uploadArea.addEventListener('drop', handleDrop);
-    uploadArea.addEventListener('click', () => document.getElementById('fileInput').click());
+
+    // Click to upload (only on the upload area, not buttons inside it)
+    uploadArea.addEventListener('click', function(event) {
+        // Only trigger file input if clicking on the upload area itself, not buttons
+        if (event.target === uploadArea || event.target.closest('.upload-content') && !event.target.closest('button')) {
+            document.getElementById('fileInput').click();
+        }
+    });
 }
 
 async function checkApiStatus() {
@@ -94,17 +101,21 @@ function handleFileSelect(event) {
 
 function handleDragOver(event) {
     event.preventDefault();
+    event.stopPropagation();
     event.currentTarget.classList.add('dragover');
 }
 
 function handleDragLeave(event) {
+    event.preventDefault();
+    event.stopPropagation();
     event.currentTarget.classList.remove('dragover');
 }
 
 function handleDrop(event) {
     event.preventDefault();
+    event.stopPropagation();
     event.currentTarget.classList.remove('dragover');
-    
+
     const files = event.dataTransfer.files;
     if (files.length > 0) {
         handleFile(files[0]);
@@ -116,23 +127,53 @@ function handleFile(file) {
         alert('Please select an image file');
         return;
     }
-    
+
     uploadedFile = file;
-    
-    // Show file info
+
+    // Show file info with change file option
     const uploadArea = document.getElementById('uploadArea');
     uploadArea.innerHTML = `
         <div class="upload-content">
             <i class="fas fa-check-circle upload-icon" style="color: #28a745;"></i>
             <p><strong>File selected:</strong> ${file.name}</p>
             <p class="upload-hint">Size: ${(file.size / 1024 / 1024).toFixed(2)} MB</p>
+            <button class="btn btn-outline" onclick="resetFileUpload()" style="margin-top: 10px;">
+                <i class="fas fa-sync-alt"></i> Change File
+            </button>
         </div>
     `;
-    
+
     // Show controls
     document.getElementById('uploadControls').style.display = 'block';
 }
 
+function resetFileUpload() {
+    uploadedFile = null;
+
+    // Reset file input
+    const fileInput = document.getElementById('fileInput');
+    fileInput.value = '';
+
+    // Reset upload area
+    const uploadArea = document.getElementById('uploadArea');
+    uploadArea.innerHTML = `
+        <div class="upload-content">
+            <i class="fas fa-cloud-upload-alt upload-icon"></i>
+            <p>Drag and drop an image here or click to select</p>
+            <p class="upload-hint">Supported formats: PNG, JPG, JPEG, GIF, BMP</p>
+            <button class="btn btn-outline" onclick="document.getElementById('fileInput').click()">
+                Select Image
+            </button>
+        </div>
+    `;
+
+    // Hide controls
+    document.getElementById('uploadControls').style.display = 'none';
+
+    // Hide results if showing
+    document.getElementById('resultsSection').style.display = 'none';
+}
+
 async function processUploadedImage() {
     if (!uploadedFile) {
         alert('Please select an image first');
@@ -157,6 +198,8 @@ async function processUploadedImage() {
 
         if (result.success) {
             displayResults(result, 'Uploaded Image Detection');
+            // Add option to upload another file
+            addUploadAnotherOption();
         } else {
             alert(`Detection failed: ${result.error}`);
         }
@@ -166,6 +209,18 @@ async function processUploadedImage() {
     }
 }
 
+function addUploadAnotherOption() {
+    const uploadControls = document.getElementById('uploadControls');
+    if (!uploadControls.querySelector('.upload-another')) {
+        const uploadAnotherBtn = document.createElement('button');
+        uploadAnotherBtn.className = 'btn btn-secondary upload-another';
+        uploadAnotherBtn.style.marginLeft = '10px';
+        uploadAnotherBtn.innerHTML = '<i class="fas fa-plus"></i> Upload Another Image';
+        uploadAnotherBtn.onclick = resetFileUpload;
+        uploadControls.appendChild(uploadAnotherBtn);
+    }
+}
+
 async function testHardcodedImage() {
     showLoading('Testing hardcoded image...');