fix: conversation filter and detail UI improvements

[NotYuSheng]

Summary

• Remove icons from Country and Device Type filter section headers
• Align Country/Device Type badge styles with other filter pills; fix empty country badge
• Add InfoPopover to Device Type filter with hint about confidence/evidence hover
• Show "Internal" label for private IPs with no geo data in conversation detail
• Remove emoji icons from device type badges everywhere

Test plan

• Open conversation filter panel — Country and Device Type headers have no icon
• Country and Device Type pills match the style of other filter pills when unselected
• No empty/blank badge appears in the Country filter
• Device Type filter tooltip mentions hovering for confidence/evidence
• In conversation detail, source IP shows "Internal" when it is a private/RFC1918 address
• Device type badges in detail and filter show label only, no emoji

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request removes device type icons from the conversation detail and filter panels, updates the styling of filter pills, and introduces logic to identify and display 'Internal' status for private IP addresses when geographic information is unavailable. Review feedback suggests optimizing the private IP detection regex to include IPv6 support, refining the country filter logic to avoid redundant string splitting, correcting the help text for device type badges to match the actual click interaction, and using a dynamic text color function for better accessibility and contrast.