Add the tier 3 utility IRC commands (closes #87)

USERHOST, VERSION, ADMIN, INFO, TIME, KILL and WALLOPS work on the
HTTP API and on the IRC listener. The USERHOST reply, the VERSION,
ADMIN and INFO text, KILL and WALLOPS are each one service function
that both transports call. User mode +w selects who receives WALLOPS.
MODE on your own nick queries or changes your user modes through one
parser on both transports: the whole mode string is checked before
anything is stored, and both flags are stored in one transaction. KILL
closes the victim's IRC connection after sending it KILL and ERROR,
without the operator waiting on it. The sessions table gains
is_wallops in 001_initial.sql, as the pre-1.0 rule in REPO_POLICIES.md
asks.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

internal/db/schema/001_initial.sql

@@ -10,6 +10,7 @@ CREATE TABLE IF NOT EXISTS sessions (
     hostname TEXT NOT NULL DEFAULT '',
     ip TEXT NOT NULL DEFAULT '',
     is_oper INTEGER NOT NULL DEFAULT 0,
+    is_wallops INTEGER NOT NULL DEFAULT 0,
     password_hash TEXT NOT NULL DEFAULT '',
     signing_key TEXT NOT NULL DEFAULT '',
     away_message TEXT NOT NULL DEFAULT '',