Sync opam package metadata including x-maintenance-intent
and external dependency specifications.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Add README files for jsonwt, owntracks, monopam, and srcsetter
- Fix langdetect language count (47→49) in dune-project
- Remove unused variable in crockford encode function
- Improve retention type documentation in zulip channels.mli
- Refactor conpool is_healthy to reduce nesting and improve clarity
- Document unimplemented IDNA features in punycode README

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Add Crockford Base32 spec link to OCaml documentation
- Add source and documentation fields to dune-project
- Fix OCaml doc references to Random module
- Update .gitignore for common build artifacts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>