Keep the issue title edit action attached to the title

Summary

At narrower viewport widths, the issue title edit button can wrap onto its own line below the title. That makes the action look detached and its purpose unclear.

Acceptance criteria

• Keep the edit button visually attached to the end of the issue title at every supported viewport width.
• The final title character and edit button must not split across separate lines.
• Long issue titles may still wrap naturally before that final title segment.
• The edit control remains keyboard-accessible, has a clear accessible name, and uses the shared tooltip behavior.
• The layout remains readable in light and dark modes without clipping or horizontal overflow.
• Add responsive rendering coverage for long and short issue titles.