feat(02-02): add file list scroll navigation and tidEDA export

- Create files.html template with scrollable file list
- Add /files route to serve the Flash Memory page
- Add POST /api/files/export endpoint for tidEDA format
- Include file count display and search/filter functionality
- Add export, view, and delete buttons for each file
- Security: prevent path traversal in file operations

Implements FILE-03 (scroll navigation) and FILE-05 (tidEDA export)

src/app.py

@@ -222,6 +222,15 @@ def calibration():
                            build_date=BUILD_DATE)
 
 
+@app.route('/files')
+def files_page():
+    """Flash memory / Files page"""
+    return render_template('files.html',
+                           page='files',
+                           version=SOFTWARE_VERSION,
+                           build_date=BUILD_DATE)
+
+
 # ==================== API ENDPOINTS ====================
 
 @app.route('/api/status')
@@ -309,6 +318,159 @@ def api_calibration_reset():
     return jsonify({"success": True})
 
 
+# ==================== FILE MANAGEMENT ====================
+
+# Logger directory - use /myvscada/logger or fall back to src/data/logger
+LOGGER_DIR = '/myvscada/logger'
+FALLBACK_LOGGER_DIR = os.path.join(os.path.dirname(__file__), 'data', 'logger')
+
+def get_logger_dir():
+    """Get the logger directory, creating fallback if needed"""
+    if os.path.exists(LOGGER_DIR):
+        return LOGGER_DIR
+    # Use fallback and ensure it exists
+    os.makedirs(FALLBACK_LOGGER_DIR, exist_ok=True)
+    return FALLBACK_LOGGER_DIR
+
+
+@app.route('/api/files')
+def api_files_list():
+    """List all CSV files in the logger directory"""
+    try:
+        logger_dir = get_logger_dir()
+        files = []
+        
+        if os.path.exists(logger_dir):
+            for filename in os.listdir(logger_dir):
+                if filename.endswith('.csv'):
+                    filepath = os.path.join(logger_dir, filename)
+                    stat = os.stat(filepath)
+                    files.append({
+                        'name': filename,
+                        'size': stat.st_size,
+                        'modified': datetime.fromtimestamp(stat.st_mtime).strftime('%Y-%m-%d %H:%M:%S'),
+                        'created': datetime.fromtimestamp(stat.st_ctime).strftime('%Y-%m-%d %H:%M:%S')
+                    })
+        
+        # Sort by creation time, newest first
+        files.sort(key=lambda x: x['created'], reverse=True)
+        
+        return jsonify({
+            'files': files,
+            'total': len(files)
+        })
+    except Exception as e:
+        return jsonify({'error': str(e), 'files': [], 'total': 0}), 500
+
+
+@app.route('/api/files/<filename>')
+def api_files_get(filename):
+    """Get contents of a specific CSV file"""
+    try:
+        # Security: prevent path traversal
+        filename = os.path.basename(filename)
+        if not filename.endswith('.csv'):
+            return jsonify({'error': 'Only CSV files are allowed'}), 400
+            
+        logger_dir = get_logger_dir()
+        filepath = os.path.join(logger_dir, filename)
+        
+        if not os.path.exists(filepath):
+            return jsonify({'error': 'File not found'}), 404
+        
+        with open(filepath, 'r') as f:
+            content = f.read()
+        
+        lines = content.split('\n')
+        # Limit preview to first 100 lines
+        preview_lines = lines[:100]
+        preview_content = '\n'.join(preview_lines)
+        
+        return jsonify({
+            'name': filename,
+            'content': preview_content,
+            'lines': len(lines),
+            'truncated': len(lines) > 100
+        })
+    except Exception as e:
+        return jsonify({'error': str(e)}), 500
+
+
+@app.route('/api/files/<filename>', methods=['DELETE'])
+def api_files_delete(filename):
+    """Delete a specific CSV file"""
+    try:
+        # Security: prevent path traversal
+        filename = os.path.basename(filename)
+        if not filename.endswith('.csv'):
+            return jsonify({'success': False, 'error': 'Only CSV files are allowed'}), 400
+            
+        logger_dir = get_logger_dir()
+        filepath = os.path.join(logger_dir, filename)
+        
+        if not os.path.exists(filepath):
+            return jsonify({'success': False, 'error': 'File not found'}), 404
+        
+        os.remove(filepath)
+        return jsonify({'success': True})
+    except Exception as e:
+        return jsonify({'success': False, 'error': str(e)}), 500
+
+
+@app.route('/api/files/export', methods=['POST'])
+def api_files_export():
+    """Generate tidEDA formatted export from CSV file"""
+    try:
+        data = request.get_json() or {}
+        filename = data.get('filename')
+        
+        if not filename:
+            return jsonify({"error": "filename required"}), 400
+        
+        # Validate filename (security: prevent path traversal)
+        if '..' in filename or '/' in filename or '\\' in filename:
+            return jsonify({"error": "invalid filename"}), 400
+        
+        # Ensure .csv extension
+        if not filename.endswith('.csv'):
+            filename = filename + '.csv'
+        
+        # Get the logger directory
+        logger_dir = get_logger_dir()
+        file_path = os.path.join(logger_dir, filename)
+        
+        if not os.path.exists(file_path):
+            return jsonify({"error": "file not found"}), 404
+        
+        # Generate tidEDA format
+        # Structure:
+        # $STATION,{station_id}
+        # $DATETIME,{timestamp}
+        # $DATA
+        # {original_csv_content}
+        # $END
+        
+        settings = load_settings()
+        station_id = settings.get("station", {}).get("id", "UNKNOWN")
+        
+        with open(file_path, 'r') as f:
+            csv_content = f.read()
+        
+        tideda_content = f"$STATION,{station_id}\n"
+        tideda_content += f"$DATETIME,{datetime.now().isoformat()}\n"
+        tideda_content += "$DATA\n"
+        tideda_content += csv_content
+        tideda_content += "$END\n"
+        
+        return jsonify({
+            "filename": filename.replace('.csv', '.tideda'),
+            "content": tideda_content,
+            "format": "tidEDA v1.0"
+        })
+    except Exception as e:
+        return jsonify({"error": str(e)}), 500
+
+
 # ==================== MAIN ====================
 
 if __name__ == '__main__':