Terminal: /report <name|#n> files a report, and /reports lists them for the owner and moderators #319

Piece of #242. Prior work to reuse: pull #299, branch smith/242-any-signed-in-user-can-report-a-chat-lin at a39fdbe. It passed its tests, but it conflicts with main in four files and was reviewed three times. Take only this piece's part of it.

Done:

• [ ] In src/terminal.ts, /report #<id> or /report <name> (that person's latest line) sends the report and prints reported #<id>.
• [ ] /reports lists reports for the owner and moderators. Anyone else is told it is for them. The owner and moderators see N reports to review: /reports on join and one line per new report.
• [ ] HELP lists both commands. Software/README.md documents them and where reports are kept.
• [ ] src/terminal.test.ts covers both commands and the refusal. bun --cwd Software/so101 test passes.