Implement all 7 utility IRC commands from issue #87:
User commands:
- USERHOST: quick lookup of user@host for up to 5 nicks (RPL 302)
- VERSION: server version string using globals.Version (RPL 351)
- ADMIN: server admin contact info (RPL 256-259)
- INFO: server software info text (RPL 371/374)
- TIME: server local time in RFC format (RPL 391)
Oper commands:
- KILL: forcibly disconnect a user (requires is_oper), broadcasts
QUIT to all shared channels, cleans up sessions
- WALLOPS: broadcast message to all users with +w usermode
(requires is_oper)
Supporting changes:
- Add is_wallops column to sessions table in 001_initial.sql
- Add user mode +w tracking via MODE nick +w/-w
- User mode queries now return actual modes (+o, +w)
- MODE -o allows de-opering yourself; MODE +o rejected
- MODE for other users returns ERR_USERSDONTMATCH (502)
- Extract dispatch helpers to reduce dispatchCommand complexity
Tests cover all commands including error cases, oper checks,
user mode set/unset, KILL broadcast, WALLOPS delivery, and
edge cases (self-kill, nonexistent users, missing params).
closes#87
