Display custom metadata in registry info text output

[JAORMX]

Summary

• Add display of custom_metadata field in text format output for thv registry info <server> command
• Custom metadata was previously only shown when using --format json
• Adds a "Custom Metadata:" section after Tags in the text output

Test plan

• Build passes
• Lint passes
• Unit tests pass
• Manually tested with thv registry info atlassian-remote which shows custom metadata

Example output

Tags:
  remote, atlassian, jira, confluence, compass, oauth, project-management, collaboration, documentation, beta

Custom Metadata:
  author: Atlassian
  homepage: https://www.atlassian.com/platform/remote-mcp-server

Example Command:
  thv run atlassian-remote

Fixes #1934

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.68%. Comparing base (a5ff43f) to head (8df4534).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2871      +/-   ##
==========================================
+ Coverage   56.66%   56.68%   +0.02%     
==========================================
  Files         322      322              
  Lines       31279    31279              
==========================================
+ Hits        17723    17731       +8     
+ Misses      12038    12026      -12     
- Partials     1518     1522       +4     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.