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

backend/main.py

@@ -43,7 +43,6 @@ app.add_middleware(
 class GenerateCopyRequest(BaseModel):
     prompt: str = Field(..., description="The main instruction for generating content")
     content_type: Optional[str] = Field(None, description="Type of content to generate")
-    tone: Optional[str] = Field(None, description="Desired tone of the content")
     length: Optional[str] = Field(None, description="Desired length of the content")
     include_cta: Optional[bool] = Field(False, description="Whether to include a call to action")
     reference_similar_content: Optional[bool] = Field(True, description="Whether to reference similar content")
@@ -88,31 +87,10 @@ async def generate_copy(request: GenerateCopyRequest):
                 }
             )
         
-        # Validate tone if provided
-        if request.tone and request.tone not in config.TONE_OPTIONS:
-            return JSONResponse(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                content={
-                    "status": "error",
-                    "message": f"Invalid tone. Must be one of: {', '.join(config.TONE_OPTIONS)}"
-                }
-            )
-        
-        # Validate length if provided
-        if request.length and request.length not in config.LENGTH_OPTIONS:
-            return JSONResponse(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                content={
-                    "status": "error",
-                    "message": f"Invalid length. Must be one of: {', '.join(config.LENGTH_OPTIONS)}"
-                }
-            )
-        
         # Generate copy
         result = await copywriter.generate_copy(
             prompt=request.prompt,
             content_type=request.content_type,
-            tone=request.tone,
             length=request.length,
             include_cta=request.include_cta,
             reference_similar_content=request.reference_similar_content,
@@ -126,7 +104,6 @@ async def generate_copy(request: GenerateCopyRequest):
         if result["content"]:
             metadata = {
                 "content_type": request.content_type,
-                "tone": request.tone,
                 "prompt": request.prompt,
                 "generated": True
             }
@@ -139,7 +116,6 @@ async def generate_copy(request: GenerateCopyRequest):
                 "prompt": request.prompt,
                 "parameters": {
                     "content_type": request.content_type,
-                    "tone": request.tone,
                     "length": request.length,
                     "include_cta": request.include_cta
                 },