feat(feedback): Add content improvement feedback system

Frontend (frontend/app.js):

- Add textarea for improvement feedback

- Add submit button with loading state

- Handle API response and display improved content

Backend (backend/copywriter.py):

- Add improve_copy() method using Cohere API

- Integrate retry mechanism for API calls

Backend (backend/main.py):

- Add /improve-content POST endpoint

- Implement error handling and return improved content with metadata

Testing:

- Verified feedback submission flow

- Confirmed improved content generation

- Tested error scenarios and loading states

.gitignore

@@ -34,9 +34,7 @@ ENV/
 *.swo
 
 # Local data
-data/past_campaigns/*
 data/user_queries/*
-!data/past_campaigns/.gitkeep
 !data/user_queries/.gitkeep
 backend/data/vector_store/*
 !backend/data/vector_store/.gitkeep