Add progress tracking and asynchronous processing to image manipulation features

Update API documentation and add new asynchronous endpoints for image processing, along with progress and result retrieval endpoints.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 2cb6c3f4-ce08-4bde-a268-54e2cdd3f036
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 05390401-1966-4200-a81a-4e10cbd0de6a
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replit.md

@@ -34,13 +34,19 @@ An AI-powered image processing API with multiple features:
 - `GET /docs` - Swagger API documentation
 - `GET /health` - Health check
 - `GET /model-info` - Model information
-- `POST /enhance` - Enhance/upscale image (Real-ESRGAN)
+- `GET /progress/{job_id}` - Get async job progress
+- `GET /result/{job_id}` - Get completed job result
+- `POST /enhance` - Enhance/upscale image (Real-ESRGAN) - supports `async_mode=true`
+- `POST /enhance/async` - Start async enhancement with progress tracking
 - `POST /enhance/base64` - Enhance image (returns base64)
-- `POST /remove-background` - Remove image background (BiRefNet)
+- `POST /remove-background` - Remove image background (BiRefNet) - supports `async_mode=true`
+- `POST /remove-background/async` - Start async background removal with progress
 - `POST /remove-background/base64` - Remove background (returns base64)
-- `POST /denoise` - Reduce image noise (OpenCV NLM)
+- `POST /denoise` - Reduce image noise (OpenCV NLM) - supports `async_mode=true`
+- `POST /denoise/async` - Start async denoising with progress
 - `POST /denoise/base64` - Denoise image (returns base64)
-- `POST /docscan` - Scan document (auto-crop, align, HD enhance)
+- `POST /docscan` - Scan document (auto-crop, align, HD enhance) - supports `async_mode=true`
+- `POST /docscan/async` - Start async document scan with progress
 - `POST /docscan/base64` - Scan document (returns base64)
 
 ## Document Scanner Features
@@ -59,7 +65,40 @@ The `/docscan` endpoint provides:
 3. Upload all files: `app.py`, `enhancer.py`, `document_scanner.py`, `templates/`, `requirements.txt`, `Dockerfile`, `README.md`
 4. The Space will auto-build the container and download AI models
 
+## Progress Tracking API
+All image processing endpoints support async mode with progress tracking:
+
+1. Start a job with `async_mode=true` or use the `/async` endpoints
+2. Receive a `job_id` in the response
+3. Poll `/progress/{job_id}` to get current progress (0-100%)
+4. When complete, fetch result from `/result/{job_id}`
+
+Example response from progress endpoint:
+```json
+{
+  "job_id": "abc-123",
+  "status": "processing",
+  "progress": 45.0,
+  "message": "Enhancing image (4 tiles)...",
+  "current_step": 2,
+  "total_steps": 5
+}
+```
+
+## Performance Optimizations
+- **Tile processing**: Images processed in 256px tiles for memory efficiency
+- **Max input size**: 512x512 for enhance (auto-resized), 2048x2048 for docscan
+- **Default scale**: 2x (faster than 4x, still good quality)
+- **Background threading**: Server stays responsive during processing
+
 ## Recent Changes
+- 2025-11-28: Added progress tracking and async processing
+  - New progress_tracker.py module with thread-safe job tracking
+  - /progress/{job_id} and /result/{job_id} endpoints
+  - async_mode parameter on all image processing endpoints
+  - Dedicated /async endpoints for each feature
+  - Automatic cleanup of old jobs and result files
+  - Performance optimizations: tile=256, max_size=512, default scale=2
 - 2025-11-28: Added document scanning feature
   - Auto-crop with edge detection and contour finding
   - Perspective correction for skewed documents