* docs(mail): clarify message read shortcuts
Update mail read shortcut help, docs, and triage guidance so single-message and multi-message reads are routed to the right commands.
Add focused tests for help text, dry-run copy, triage stderr hints, and batch_get chunking behavior.
sprint: S1
* docs(mail): align batch_get limit with gateway config
* docs(mail): use shell-safe batch message id examples
* docs(mail): trim batch_get pagination wording
* docs(mail): use placeholder style for message ids
* docs(mail): hide batch_get internals from help