Release v0.3.2 · rameerez/chats

Three correctness fixes and one new seam, from an integration review against a real host.

Fixed

A busy stack can no longer evict other people from the inbox. The grouped-inbox window is now taken per counterpart, so one desk with many recent conversations cannot consume another counterpart's row. At most twice the row limit is materialized.
Lifecycle events fire after commit, and stay silent on rollback. conversation_created and participant_left previously ran inside the transaction, so a subscriber could act on a conversation that never existed.
An author no longer has to be a messager. Signing a desk's reply is about who wrote it, not about holding a seat, so staff need not be given acts_as_messager just to sign. The author must be persisted; the host decides who may sign for a shared identity, and the HTTP controller never accepts an author from request parameters.

Chats::SendRateLimited — the send-rate budget as a controller concern, so a product built on chats (its own composer, its own controller) shares one configured budget with the chat composer instead of inventing a second one.
```
config.send_rate_limit = { to: 60, within: 1.minute }  # shared; nil disables
```

Nothing to do. If you were relying on an author having to be a messager, note that constraint is gone by design.

Full Changelog: v0.3.1...v0.3.2