feat(daemon): resident session, auth-gated control socket, and event fan-out

The daemon drains the library's destructive take_* accessors once and fans
events out per connection, which is what lets more than one client share a
session. A Unix socket at 0600 is the local transport and its permissions
are the authentication; TCP is opt-in and needs the generated token. Rooms,
transfers, and the conversation are daemon-owned and restored on restart.

Cargo.lock

@@ -2553,6 +2553,7 @@ dependencies = [
  "color-eyre",
  "directories",
  "dotenv",
+ "getrandom 0.4.3",
  "igd-next",
  "keyring",
  "ratatui",