fix(zsxq): separate content field from title, remove title truncation

[Pandas886]

Summary

• Split getTopicText to return only title, add getTopicContent for body text
• Remove .slice(0, 120) that was truncating titles
• content field now contains full body text instead of duplicating title

Problem

• title was being truncated to 120 characters
• content field was identical to title (both used the same getTopicText function)

Solution

• getTopicText now returns only topic.title
• New getTopicContent function extracts body text from talk.text, question.text, etc.
• toTopicRow uses getTopicContent for the content field

Testing

Verified with json/yaml/plain/md/csv formats - content now shows full text.

[Pandas886]

Without the full content, truncated titles alone have limited usefulness. This fix ensures users get actual body text when querying topics.