fix: improve empty repository URL error

[netoverlord]

Fixes #453

Summary

This PR fixes a bug where a single space (" ") as input_text caused an empty digest response.

• whitespace-only inputs now raise {"error": "Invalid repository URL: cannot be empty or spaces only."}.

[github-actions]

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[MickaelCa]

Hello, and thank you for your PR!

The returned error should be the same as what we have for invalid repository URL so that the front-end can display them properly

url 'https://pr-454.gitingest.coderamp.dev/api/ingest' \
  -X POST \
  -H 'Content-Type: application/json' \
  --data-raw '{"input_text":" ","token":"","max_file_size":"243","pattern_type":"exclude","pattern":""}'
{"detail":[{"type":"value_error","loc":["body","input_text"],"msg":"Value error, input_text cannot be empty","input":" ","ctx":{"error":{}}}]}

curl 'https://pr-454.gitingest.coderamp.dev/api/ingest' \
  -X POST \
  -H 'Content-Type: application/json' \
  --data-raw '{"input_text":"agaga","token":"","max_file_size":"243","pattern_type":"exclude","pattern":""}'
{"error":"Invalid repository URL 'agaga'"}

[netoverlord]

It returns:
{"error": "Invalid repository URL: cannot be empty or spaces only."}
and it works correctly in the frontend

[github-actions]

Hi there! We haven’t seen activity on this pull request for 45 days, so I’m marking it as stale.
If you’d like to keep it open, please leave a comment within 10 days. Thanks!

[github-actions]

Hi there! We haven’t heard anything for 10 days, so I’m closing this pull request. Feel free to reopen if you’d like to continue working on it. Thanks!