Improve suggestions API

[satwikkansal]

Description

Brief description of what this PR does and why.

Checklist

• I have created an issue for this change (not mandatory for small changes)
• My changes are to-the-point
• Code is styled as the rest of the codebase and linting passes
• I have tested my changes locally and they work as expected
• I have updated the documentation (if needed)
• I have reviewed the code myself once and I don't see any issues

Additional Notes

Any additional context or notes for reviewers.

[cloudflare-workers-and-pages]

Deploying mxtoai-backend with    Cloudflare Pages

Latest commit:	25f1597
Status:	✅  Deploy successful!
Preview URL:	https://14998d4f.mxtoai-backend.pages.dev
Branch Preview URL:	https://suggestions.mxtoai-backend.pages.dev

View logs

[Copilot]

Pull Request Overview

This PR centralizes suggestion count limits with new constants, updates the prompt and logic to use these limits, shifts error handling to HTTP exceptions, and enhances logging configuration.

• Introduce MIN_SUGGESTIONS and MAX_SUGGESTIONS constants and update prompt templates and suggestion-building logic.
• Change API error flows to raise HTTPException (403/500) instead of embedding error suggestions.
• Update tests to expect at least 3 suggestions and verify HTTP status codes; make logs directory configurable and update Dockerfile.

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/test_suggestions.py	Bumped expected minimum suggestions from 2 to 3 in tests.
tests/test_api.py	Assert 403/500 status codes and check detail in error responses.
mxtoai/suggestions.py	Added MIN/MAX constants, updated docs and suggestion-combining logic.
mxtoai/api.py	Switched to raising HTTPException for whitelist and processing errors.
mxtoai/_logging.py	Made logs directory configurable and guarded file handlers.
docker/api_server.dockerfile	Create /app/logs directory for file logging.