fix: prefill abuse report summary from chat message

[santoslgl01-web]

Summary

• prefill the abuse report summary field from the selected chat line
• keep the full selected chat text in the abuse report details field
• trim the summary to a single line that fits the report form limit

Testing

• git diff --check
• python3 targeted source assertions to confirm the updated call path and summary prefill

Fixes #5744

[github-actions]

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[chatgpt-codex-connector]

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[santoslgl01-web]

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[santoslgl01-web]

recheck